656881920 has 288 divisors, whose sum is σ = 2369404800. Its totient is φ = 172302336.

The previous prime is 656881903. The next prime is 656881933. The reversal of 656881920 is 29188656.

656881920 is a `hidden beast` number, since 6 + 568 + 81 + 9 + 2 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2868366 + ... + 2868594.

It is an arithmetic number, because the mean of its divisors is an integer number (8227100).

Almost surely, 2^656881920 is an apocalyptic number.

656881920 is a gapful number since it is divisible by the number (60) 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 656881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1184702400).

656881920 is an abundant number, since it is smaller than the sum of its proper divisors (1712522880).

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

656881920 is a wasteful number, since it uses less digits than its factorization.

656881920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The square root of 656881920 is about 25629.7077626726. The cubic root of 656881920 is about 869.2855013600.

It can be divided in two parts, 6568 and 81920, that added together give a palindrome (88488).

The spelling of 656881920 in words is "six hundred fifty-six million, eight hundred eighty-one thousand, nine hundred twenty".