21023402137 has 2 divisors, whose sum is σ = 21023402138. Its totient is φ = 21023402136.

The previous prime is 21023402119. The next prime is 21023402171. The reversal of 21023402137 is 73120432012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20845873161 + 177528976 = 144381^2 + 13324^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023402137 - 2⁷ = 21023402009 is a prime.

It is not a weakly prime, because it can be changed into another prime (21023402437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511701068 + 10511701069.

It is an arithmetic number, because the mean of its divisors is an integer number (10511701069).

Almost surely, 2^21023402137 is an apocalyptic number.

It is an amenable number.

21023402137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023402137 is an equidigital number, since it uses as much as digits as its factorization.

21023402137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 25.

Adding to 21023402137 its reverse (73120432012), we get a palindrome (94143834149).

The spelling of 21023402137 in words is "twenty-one billion, twenty-three million, four hundred two thousand, one hundred thirty-seven".