21537192779 has 2 divisors, whose sum is σ = 21537192780. Its totient is φ = 21537192778.

The previous prime is 21537192773. The next prime is 21537192811. The reversal of 21537192779 is 97729173512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21537192779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21537192779.

It is not a weakly prime, because it can be changed into another prime (21537192773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10768596389 + 10768596390.

It is an arithmetic number, because the mean of its divisors is an integer number (10768596390).

Almost surely, 2^21537192779 is an apocalyptic number.

21537192779 is a deficient number, since it is larger than the sum of its proper divisors (1).

21537192779 is an equidigital number, since it uses as much as digits as its factorization.

21537192779 is an evil number, because the sum of its binary digits is even.

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

The spelling of 21537192779 in words is "twenty-one billion, five hundred thirty-seven million, one hundred ninety-two thousand, seven hundred seventy-nine".