21738934565437 has 2 divisors, whose sum is σ = 21738934565438. Its totient is φ = 21738934565436.

The previous prime is 21738934565431. The next prime is 21738934565507. The reversal of 21738934565437 is 73456543983712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21170940213721 + 567994351716 = 4601189^2 + 753654^2 .

It is a cyclic number.

It is not a de Polignac number, because 21738934565437 - 2²³ = 21738926176829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21738934565431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10869467282718 + 10869467282719.

It is an arithmetic number, because the mean of its divisors is an integer number (10869467282719).

Almost surely, 2^{21738934565437} is an apocalyptic number.

It is an amenable number.

21738934565437 is a deficient number, since it is larger than the sum of its proper divisors (1).

21738934565437 is an equidigital number, since it uses as much as digits as its factorization.

21738934565437 is an evil number, because the sum of its binary digits is even.

The product of its digits is 457228800, while the sum is 67.

The spelling of 21738934565437 in words is "twenty-one trillion, seven hundred thirty-eight billion, nine hundred thirty-four million, five hundred sixty-five thousand, four hundred thirty-seven".