21751673831 has 4 divisors (see below), whose sum is σ = 21777055872. Its totient is φ = 21726291792.

The previous prime is 21751673821. The next prime is 21751673861. The reversal of 21751673831 is 13837615712.

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 21751673831 - 2¹⁸ = 21751411687 is a prime.

It is a super-2 number, since 2×21751673831² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21751673821) 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, 12689735 + ... + 12691448.

It is an arithmetic number, because the mean of its divisors is an integer number (5444263968).

Almost surely, 2^21751673831 is an apocalyptic number.

21751673831 is a deficient number, since it is larger than the sum of its proper divisors (25382041).

21751673831 is an equidigital number, since it uses as much as digits as its factorization.

21751673831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25382040.

The product of its digits is 211680, while the sum is 44.

The spelling of 21751673831 in words is "twenty-one billion, seven hundred fifty-one million, six hundred seventy-three thousand, eight hundred thirty-one".