661521792 has 32 divisors (see below), whose sum is σ = 1757168280. Its totient is φ = 220507136.

The previous prime is 661521769. The next prime is 661521793. The reversal of 661521792 is 297125166.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×661521792² = 875222162581782528, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 661521792.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661521793) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 860973 + ... + 861740.

Almost surely, 2^661521792 is an apocalyptic number.

It is an amenable number.

661521792 is an abundant number, since it is smaller than the sum of its proper divisors (1095646488).

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

661521792 is a wasteful number, since it uses less digits than its factorization.

661521792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1722730 (or 1722718 counting only the distinct ones).

The product of its digits is 45360, while the sum is 39.

The square root of 661521792 is about 25720.0659408175. The cubic root of 661521792 is about 871.3274279611.

The spelling of 661521792 in words is "six hundred sixty-one million, five hundred twenty-one thousand, seven hundred ninety-two".