725656321 has 32 divisors (see below), whose sum is σ = 824165888. Its totient is φ = 634521600.

The previous prime is 725656319. The next prime is 725656363. The reversal of 725656321 is 123656527.

It is a cyclic number.

It is not a de Polignac number, because 725656321 - 2¹ = 725656319 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (725656381) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4805596 + ... + 4805746.

It is an arithmetic number, because the mean of its divisors is an integer number (25755184).

Almost surely, 2^725656321 is an apocalyptic number.

725656321 is the 15553-rd octagonal number.

It is an amenable number.

725656321 is a deficient number, since it is larger than the sum of its proper divisors (98509567).

725656321 is a wasteful number, since it uses less digits than its factorization.

725656321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401.

The product of its digits is 75600, while the sum is 37.

The square root of 725656321 is about 26938.0088536625. The cubic root of 725656321 is about 898.6218912846.

The spelling of 725656321 in words is "seven hundred twenty-five million, six hundred fifty-six thousand, three hundred twenty-one".