661136256 has 480 divisors, whose sum is σ = 2363739840. Its totient is φ = 182476800.

The previous prime is 661136243. The next prime is 661136261. The reversal of 661136256 is 652631166.

661136256 is a `hidden beast` number, since 6 + 611 + 36 + 2 + 5 + 6 = 666.

It is a super-2 number, since 2×661136256² = 874202297995395072, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (38880) is a multiple of the sum of its prime factors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 661136256.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 21326961 + ... + 21326991.

It is an arithmetic number, because the mean of its divisors is an integer number (4924458).

Almost surely, 2^661136256 is an apocalyptic number.

661136256 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661136256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1181869920).

661136256 is an abundant number, since it is smaller than the sum of its proper divisors (1702603584).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661136256 is a wasteful number, since it uses less digits than its factorization.

661136256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 64 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 661136256 is about 25712.5699999047. The cubic root of 661136256 is about 871.1581247090.

The spelling of 661136256 in words is "six hundred sixty-one million, one hundred thirty-six thousand, two hundred fifty-six".