21758238231 has 4 divisors (see below), whose sum is σ = 29010984312. Its totient is φ = 14505492152.

The previous prime is 21758238221. The next prime is 21758238251. The reversal of 21758238231 is 13283285712.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21758238231 - 2¹¹ = 21758236183 is a prime.

It is a super-2 number, since 2×21758238231² (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 (21758238221) 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, 3626373036 + ... + 3626373041.

It is an arithmetic number, because the mean of its divisors is an integer number (7252746078).

Almost surely, 2^21758238231 is an apocalyptic number.

21758238231 is a deficient number, since it is larger than the sum of its proper divisors (7252746081).

21758238231 is an equidigital number, since it uses as much as digits as its factorization.

21758238231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7252746080.

The product of its digits is 161280, while the sum is 42.

The spelling of 21758238231 in words is "twenty-one billion, seven hundred fifty-eight million, two hundred thirty-eight thousand, two hundred thirty-one".