21642037049 has 2 divisors, whose sum is σ = 21642037050. Its totient is φ = 21642037048.

The previous prime is 21642036989. The next prime is 21642037061. The reversal of 21642037049 is 94073024612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13547796025 + 8094241024 = 116395^2 + 89968^2 .

It is a cyclic number.

It is not a de Polignac number, because 21642037049 - 2¹² = 21642032953 is a prime.

It is not a weakly prime, because it can be changed into another prime (21642037349) 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, 10821018524 + 10821018525.

It is an arithmetic number, because the mean of its divisors is an integer number (10821018525).

Almost surely, 2^21642037049 is an apocalyptic number.

It is an amenable number.

21642037049 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642037049 is an equidigital number, since it uses as much as digits as its factorization.

21642037049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 38.

The spelling of 21642037049 in words is "twenty-one billion, six hundred forty-two million, thirty-seven thousand, forty-nine".