21879537637 has 2 divisors, whose sum is σ = 21879537638. Its totient is φ = 21879537636.

The previous prime is 21879537613. The next prime is 21879537653. The reversal of 21879537637 is 73673597812.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21807610276 + 71927361 = 147674^2 + 8481^2 .

It is a cyclic number.

It is not a de Polignac number, because 21879537637 - 2¹⁵ = 21879504869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21879537677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10939768818 + 10939768819.

It is an arithmetic number, because the mean of its divisors is an integer number (10939768819).

Almost surely, 2^21879537637 is an apocalyptic number.

It is an amenable number.

21879537637 is a deficient number, since it is larger than the sum of its proper divisors (1).

21879537637 is an equidigital number, since it uses as much as digits as its factorization.

21879537637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13335840, while the sum is 58.

The spelling of 21879537637 in words is "twenty-one billion, eight hundred seventy-nine million, five hundred thirty-seven thousand, six hundred thirty-seven".