725618921 has 2 divisors, whose sum is σ = 725618922. Its totient is φ = 725618920.

The previous prime is 725618903. The next prime is 725618941. The reversal of 725618921 is 129816527.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 604618921 + 121000000 = 24589^2 + 11000^2 .

It is a cyclic number.

It is not a de Polignac number, because 725618921 - 2⁶ = 725618857 is a prime.

It is a Chen prime.

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

It is not a weakly prime, because it can be changed into another prime (725618941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 362809460 + 362809461.

It is an arithmetic number, because the mean of its divisors is an integer number (362809461).

Almost surely, 2^725618921 is an apocalyptic number.

It is an amenable number.

725618921 is a deficient number, since it is larger than the sum of its proper divisors (1).

725618921 is an equidigital number, since it uses as much as digits as its factorization.

725618921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60480, while the sum is 41.

The square root of 725618921 is about 26937.3146582951. The cubic root of 725618921 is about 898.6064528301.

The spelling of 725618921 in words is "seven hundred twenty-five million, six hundred eighteen thousand, nine hundred twenty-one".