661974880 has 192 divisors, whose sum is σ = 1877904000. Its totient is φ = 215728128.

The previous prime is 661974869. The next prime is 661974913. The reversal of 661974880 is 88479166.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2890606 + ... + 2890834.

It is an arithmetic number, because the mean of its divisors is an integer number (9780750).

Almost surely, 2^661974880 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 661974880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (938952000).

661974880 is an abundant number, since it is smaller than the sum of its proper divisors (1215929120).

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

661974880 is a wasteful number, since it uses less digits than its factorization.

661974880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369 (or 361 counting only the distinct ones).

The product of its (nonzero) digits is 580608, while the sum is 49.

The square root of 661974880 is about 25728.8724976436. The cubic root of 661974880 is about 871.5263117612.

The spelling of 661974880 in words is "six hundred sixty-one million, nine hundred seventy-four thousand, eight hundred eighty".