21197239577 has 2 divisors, whose sum is σ = 21197239578. Its totient is φ = 21197239576.

The previous prime is 21197239529. The next prime is 21197239603. The reversal of 21197239577 is 77593279112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14806995856 + 6390243721 = 121684^2 + 79939^2 .

It is a cyclic number.

It is not a de Polignac number, because 21197239577 - 2¹² = 21197235481 is a prime.

It is not a weakly prime, because it can be changed into another prime (21197230577) 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, 10598619788 + 10598619789.

It is an arithmetic number, because the mean of its divisors is an integer number (10598619789).

Almost surely, 2^21197239577 is an apocalyptic number.

It is an amenable number.

21197239577 is a deficient number, since it is larger than the sum of its proper divisors (1).

21197239577 is an equidigital number, since it uses as much as digits as its factorization.

21197239577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1666980, while the sum is 53.

The spelling of 21197239577 in words is "twenty-one billion, one hundred ninety-seven million, two hundred thirty-nine thousand, five hundred seventy-seven".