21211870457 has 2 divisors, whose sum is σ = 21211870458. Its totient is φ = 21211870456.

The previous prime is 21211870439. The next prime is 21211870481. The reversal of 21211870457 is 75407811212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11981272681 + 9230597776 = 109459^2 + 96076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211870457 - 2²⁸ = 20943435001 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21211870457.

It is not a weakly prime, because it can be changed into another prime (21211860457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605935228 + 10605935229.

It is an arithmetic number, because the mean of its divisors is an integer number (10605935229).

Almost surely, 2^21211870457 is an apocalyptic number.

It is an amenable number.

21211870457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211870457 is an equidigital number, since it uses as much as digits as its factorization.

21211870457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 31360, while the sum is 38.

The spelling of 21211870457 in words is "twenty-one billion, two hundred eleven million, eight hundred seventy thousand, four hundred fifty-seven".