21637029789 has 6 divisors (see below), whose sum is σ = 31253487486. Its totient is φ = 14424686520.

The previous prime is 21637029767. The next prime is 21637029823. The reversal of 21637029789 is 98792073612.

It can be written as a sum of positive squares in only one way, i.e., 21314540025 + 322489764 = 145995^2 + 17958^2 .

It is not a de Polignac number, because 21637029789 - 2¹⁶ = 21636964253 is a prime.

It is a super-2 number, since 2×21637029789² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21637029709) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1202057202 + ... + 1202057219.

It is an arithmetic number, because the mean of its divisors is an integer number (5208914581).

Almost surely, 2^21637029789 is an apocalyptic number.

It is an amenable number.

21637029789 is a deficient number, since it is larger than the sum of its proper divisors (9616457697).

21637029789 is a wasteful number, since it uses less digits than its factorization.

21637029789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2404114427 (or 2404114424 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 54.

The spelling of 21637029789 in words is "twenty-one billion, six hundred thirty-seven million, twenty-nine thousand, seven hundred eighty-nine".