20724577637 has 2 divisors, whose sum is σ = 20724577638. Its totient is φ = 20724577636.

The previous prime is 20724577619. The next prime is 20724577703. The reversal of 20724577637 is 73677542702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16962718081 + 3761859556 = 130241^2 + 61334^2 .

It is a cyclic number.

It is not a de Polignac number, because 20724577637 - 2²⁸ = 20456142181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20724577607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10362288818 + 10362288819.

It is an arithmetic number, because the mean of its divisors is an integer number (10362288819).

Almost surely, 2^20724577637 is an apocalyptic number.

It is an amenable number.

20724577637 is a deficient number, since it is larger than the sum of its proper divisors (1).

20724577637 is an equidigital number, since it uses as much as digits as its factorization.

20724577637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3457440, while the sum is 50.

The spelling of 20724577637 in words is "twenty billion, seven hundred twenty-four million, five hundred seventy-seven thousand, six hundred thirty-seven".