656389440 has 224 divisors, whose sum is σ = 2646639360. Its totient is φ = 150018048.

The previous prime is 656389429. The next prime is 656389469. The reversal of 656389440 is 44983656.

656389440 is a `hidden beast` number, since 6 + 5 + 638 + 9 + 4 + 4 + 0 = 666.

656389440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (224).

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, 55054 + ... + 65906.

Almost surely, 2^656389440 is an apocalyptic number.

656389440 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 656389440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1323319680).

656389440 is an abundant number, since it is smaller than the sum of its proper divisors (1990249920).

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

656389440 is a wasteful number, since it uses less digits than its factorization.

656389440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10886 (or 10870 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The square root of 656389440 is about 25620.0983604669. The cubic root of 656389440 is about 869.0682057080.

It can be divided in two parts, 65638 and 9440, that added together give a triangular number (75078 = T₃₈₇).

The spelling of 656389440 in words is "six hundred fifty-six million, three hundred eighty-nine thousand, four hundred forty".