21089656057 has 2 divisors, whose sum is σ = 21089656058. Its totient is φ = 21089656056.

The previous prime is 21089656037. The next prime is 21089656069. The reversal of 21089656057 is 75065698012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14272841961 + 6816814096 = 119469^2 + 82564^2 .

It is a cyclic number.

It is not a de Polignac number, because 21089656057 - 2¹⁹ = 21089131769 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21089656057.

It is not a weakly prime, because it can be changed into another prime (21089656037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10544828028 + 10544828029.

It is an arithmetic number, because the mean of its divisors is an integer number (10544828029).

Almost surely, 2^21089656057 is an apocalyptic number.

It is an amenable number.

21089656057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21089656057 is an equidigital number, since it uses as much as digits as its factorization.

21089656057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 49.

The spelling of 21089656057 in words is "twenty-one billion, eighty-nine million, six hundred fifty-six thousand, fifty-seven".