20915970457 has 2 divisors, whose sum is σ = 20915970458. Its totient is φ = 20915970456.

The previous prime is 20915970371. The next prime is 20915970521. The reversal of 20915970457 is 75407951902.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12069439321 + 8846531136 = 109861^2 + 94056^2 .

It is a cyclic number.

It is not a de Polignac number, because 20915970457 - 2¹⁹ = 20915446169 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20915970457.

It is not a weakly prime, because it can be changed into another prime (20915970557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10457985228 + 10457985229.

It is an arithmetic number, because the mean of its divisors is an integer number (10457985229).

Almost surely, 2^20915970457 is an apocalyptic number.

It is an amenable number.

20915970457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20915970457 is an equidigital number, since it uses as much as digits as its factorization.

20915970457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 793800, while the sum is 49.

The spelling of 20915970457 in words is "twenty billion, nine hundred fifteen million, nine hundred seventy thousand, four hundred fifty-seven".