661396752 has 100 divisors (see below), whose sum is σ = 1950595020. Its totient is φ = 216283392.

The previous prime is 661396739. The next prime is 661396877. The reversal of 661396752 is 257693166.

It can be written as a sum of positive squares in 2 ways, for example, as 592240896 + 69155856 = 24336^2 + 8316^2 .

It is a super-2 number, since 2×661396752² = 874891327112299008, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661396698 and 661396707.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 63874 + ... + 73502.

Almost surely, 2^661396752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661396752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (975297510).

661396752 is an abundant number, since it is smaller than the sum of its proper divisors (1289198268).

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

661396752 is a wasteful number, since it uses less digits than its factorization.

661396752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9702 (or 9687 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 661396752 is about 25717.6350390155. The cubic root of 661396752 is about 871.2725254378.

The spelling of 661396752 in words is "six hundred sixty-one million, three hundred ninety-six thousand, seven hundred fifty-two".