21971793637 has 8 divisors (see below), whose sum is σ = 22452206976. Its totient is φ = 21491919072.

The previous prime is 21971793631. The next prime is 21971793659. The reversal of 21971793637 is 73639717912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21971793637 - 2¹⁹ = 21971269349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21971793631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51688 + ... + 215905.

It is an arithmetic number, because the mean of its divisors is an integer number (2806525872).

Almost surely, 2^21971793637 is an apocalyptic number.

It is an amenable number.

21971793637 is a deficient number, since it is larger than the sum of its proper divisors (480413339).

21971793637 is a wasteful number, since it uses less digits than its factorization.

21971793637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269387.

The product of its digits is 3000564, while the sum is 55.

The spelling of 21971793637 in words is "twenty-one billion, nine hundred seventy-one million, seven hundred ninety-three thousand, six hundred thirty-seven".