915607921 has 2 divisors, whose sum is σ = 915607922. Its totient is φ = 915607920.

The previous prime is 915607919. The next prime is 915607939. The reversal of 915607921 is 129706519.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 830304225 + 85303696 = 28815^2 + 9236^2 .

It is a cyclic number.

It is not a de Polignac number, because 915607921 - 2¹ = 915607919 is a prime.

Together with 915607919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (915607951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 457803960 + 457803961.

It is an arithmetic number, because the mean of its divisors is an integer number (457803961).

Almost surely, 2^915607921 is an apocalyptic number.

It is an amenable number.

915607921 is a deficient number, since it is larger than the sum of its proper divisors (1).

915607921 is an equidigital number, since it uses as much as digits as its factorization.

915607921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 40.

The square root of 915607921 is about 30259.0138801647. The cubic root of 915607921 is about 971.0386440732.

The spelling of 915607921 in words is "nine hundred fifteen million, six hundred seven thousand, nine hundred twenty-one".