661995264 has 144 divisors (see below), whose sum is σ = 2119873280. Its totient is φ = 179159040.

The previous prime is 661995239. The next prime is 661995311. The reversal of 661995264 is 462599166.

661995264 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×661995264³ (a number of 27 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98904 + ... + 105384.

Almost surely, 2^661995264 is an apocalyptic number.

661995264 is a gapful number since it is divisible by the number (64) 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 661995264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059936640).

661995264 is an abundant number, since it is smaller than the sum of its proper divisors (1457878016).

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

661995264 is a wasteful number, since it uses less digits than its factorization.

661995264 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6526 (or 6512 counting only the distinct ones).

The product of its digits is 699840, while the sum is 48.

The square root of 661995264 is about 25729.2686254390. The cubic root of 661995264 is about 871.5352572215.

The spelling of 661995264 in words is "six hundred sixty-one million, nine hundred ninety-five thousand, two hundred sixty-four".