21641233637 has 4 divisors (see below), whose sum is σ = 21736569696. Its totient is φ = 21545897580.

The previous prime is 21641233619. The next prime is 21641233697. The reversal of 21641233637 is 73633214612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21641233637 - 2⁶ = 21641233573 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21641233637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641233697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47667689 + ... + 47668142.

It is an arithmetic number, because the mean of its divisors is an integer number (5434142424).

Almost surely, 2^21641233637 is an apocalyptic number.

It is an amenable number.

21641233637 is a deficient number, since it is larger than the sum of its proper divisors (95336059).

21641233637 is an equidigital number, since it uses as much as digits as its factorization.

21641233637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95336058.

The product of its digits is 108864, while the sum is 38.

The spelling of 21641233637 in words is "twenty-one billion, six hundred forty-one million, two hundred thirty-three thousand, six hundred thirty-seven".