21002012137 has 2 divisors, whose sum is σ = 21002012138. Its totient is φ = 21002012136.

The previous prime is 21002012107. The next prime is 21002012147. The reversal of 21002012137 is 73121020012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12840515856 + 8161496281 = 113316^2 + 90341^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002012137 - 2³¹ = 18854528489 is a prime.

It is not a weakly prime, because it can be changed into another prime (21002012107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501006068 + 10501006069.

It is an arithmetic number, because the mean of its divisors is an integer number (10501006069).

Almost surely, 2^21002012137 is an apocalyptic number.

It is an amenable number.

21002012137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002012137 is an equidigital number, since it uses as much as digits as its factorization.

21002012137 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168, while the sum is 19.

Adding to 21002012137 its reverse (73121020012), we get a palindrome (94123032149).

The spelling of 21002012137 in words is "twenty-one billion, two million, twelve thousand, one hundred thirty-seven".