21190570721 has 2 divisors, whose sum is σ = 21190570722. Its totient is φ = 21190570720.

The previous prime is 21190570693. The next prime is 21190570741. The reversal of 21190570721 is 12707509112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20609760721 + 580810000 = 143561^2 + 24100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21190570721 - 2¹⁸ = 21190308577 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21190570741) 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, 10595285360 + 10595285361.

It is an arithmetic number, because the mean of its divisors is an integer number (10595285361).

Almost surely, 2^21190570721 is an apocalyptic number.

It is an amenable number.

21190570721 is a deficient number, since it is larger than the sum of its proper divisors (1).

21190570721 is an equidigital number, since it uses as much as digits as its factorization.

21190570721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8820, while the sum is 35.

The spelling of 21190570721 in words is "twenty-one billion, one hundred ninety million, five hundred seventy thousand, seven hundred twenty-one".