21179240387237 has 2 divisors, whose sum is σ = 21179240387238. Its totient is φ = 21179240387236.

The previous prime is 21179240387219. The next prime is 21179240387281. The reversal of 21179240387237 is 73278304297112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14739694671361 + 6439545715876 = 3839231^2 + 2537626^2 .

It is a cyclic number.

It is not a de Polignac number, because 21179240387237 - 2³⁸ = 20904362480293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21179240377237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10589620193618 + 10589620193619.

It is an arithmetic number, because the mean of its divisors is an integer number (10589620193619).

Almost surely, 2^{21179240387237} is an apocalyptic number.

It is an amenable number.

21179240387237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21179240387237 is an equidigital number, since it uses as much as digits as its factorization.

21179240387237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7112448, while the sum is 56.

The spelling of 21179240387237 in words is "twenty-one trillion, one hundred seventy-nine billion, two hundred forty million, three hundred eighty-seven thousand, two hundred thirty-seven".