21144315197 has 2 divisors, whose sum is σ = 21144315198. Its totient is φ = 21144315196.

The previous prime is 21144315107. The next prime is 21144315271. The reversal of 21144315197 is 79151344112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14595297721 + 6549017476 = 120811^2 + 80926^2 .

It is a cyclic number.

It is not a de Polignac number, because 21144315197 - 2⁸ = 21144314941 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21144315197.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21144315107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10572157598 + 10572157599.

It is an arithmetic number, because the mean of its divisors is an integer number (10572157599).

Almost surely, 2^21144315197 is an apocalyptic number.

It is an amenable number.

21144315197 is a deficient number, since it is larger than the sum of its proper divisors (1).

21144315197 is an equidigital number, since it uses as much as digits as its factorization.

21144315197 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 38.

The spelling of 21144315197 in words is "twenty-one billion, one hundred forty-four million, three hundred fifteen thousand, one hundred ninety-seven".