21764207537 has 2 divisors, whose sum is σ = 21764207538. Its totient is φ = 21764207536.

The previous prime is 21764207519. The next prime is 21764207579. The reversal of 21764207537 is 73570246712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19531739536 + 2232468001 = 139756^2 + 47249^2 .

It is a cyclic number.

It is not a de Polignac number, because 21764207537 - 2⁸ = 21764207281 is a prime.

It is not a weakly prime, because it can be changed into another prime (21764207137) 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, 10882103768 + 10882103769.

It is an arithmetic number, because the mean of its divisors is an integer number (10882103769).

Almost surely, 2^21764207537 is an apocalyptic number.

It is an amenable number.

21764207537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764207537 is an equidigital number, since it uses as much as digits as its factorization.

21764207537 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 493920, while the sum is 44.

The spelling of 21764207537 in words is "twenty-one billion, seven hundred sixty-four million, two hundred seven thousand, five hundred thirty-seven".