21638793 has 12 divisors (see below), whose sum is σ = 31713584. Its totient is φ = 13114200.

The previous prime is 21638767. The next prime is 21638797. The reversal of 21638793 is 39783612.

It is not a de Polignac number, because 21638793 - 2¹³ = 21630601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21638797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29443 + ... + 30168.

Almost surely, 2^21638793 is an apocalyptic number.

It is an amenable number.

21638793 is a deficient number, since it is larger than the sum of its proper divisors (10074791).

21638793 is a wasteful number, since it uses less digits than its factorization.

21638793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59636 (or 59625 counting only the distinct ones).

The product of its digits is 54432, while the sum is 39.

The square root of 21638793 is about 4651.7516055783. The cubic root of 21638793 is about 278.6619535983.

The spelling of 21638793 in words is "twenty-one million, six hundred thirty-eight thousand, seven hundred ninety-three".