915395021 has 2 divisors, whose sum is σ = 915395022. Its totient is φ = 915395020.

The previous prime is 915394981. The next prime is 915395023. The reversal of 915395021 is 120593519.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 473932900 + 441462121 = 21770^2 + 21011^2 .

It is a cyclic number.

It is not a de Polignac number, because 915395021 - 2⁶ = 915394957 is a prime.

It is a Sophie Germain prime.

Together with 915395023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (915395023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 457697510 + 457697511.

It is an arithmetic number, because the mean of its divisors is an integer number (457697511).

Almost surely, 2^915395021 is an apocalyptic number.

It is an amenable number.

915395021 is a deficient number, since it is larger than the sum of its proper divisors (1).

915395021 is an equidigital number, since it uses as much as digits as its factorization.

915395021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12150, while the sum is 35.

The square root of 915395021 is about 30255.4957156547. The cubic root of 915395021 is about 970.9633752643.

The spelling of 915395021 in words is "nine hundred fifteen million, three hundred ninety-five thousand, twenty-one".