21764207137 has 2 divisors, whose sum is σ = 21764207138. Its totient is φ = 21764207136.

The previous prime is 21764207089. The next prime is 21764207219. The reversal of 21764207137 is 73170246712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19937157601 + 1827049536 = 141199^2 + 42744^2 .

It is a cyclic number.

It is not a de Polignac number, because 21764207137 - 2¹⁹ = 21763682849 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21764207137.

It is not a weakly prime, because it can be changed into another prime (21764207537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10882103568 + 10882103569.

It is an arithmetic number, because the mean of its divisors is an integer number (10882103569).

Almost surely, 2^21764207137 is an apocalyptic number.

It is an amenable number.

21764207137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21764207137 is an equidigital number, since it uses as much as digits as its factorization.

21764207137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 98784, while the sum is 40.

The spelling of 21764207137 in words is "twenty-one billion, seven hundred sixty-four million, two hundred seven thousand, one hundred thirty-seven".