21952831 has 4 divisors (see below), whose sum is σ = 23244192. Its totient is φ = 20661472.

The previous prime is 21952823. The next prime is 21952841. The reversal of 21952831 is 13825912.

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 21952831 - 2³ = 21952823 is a prime.

It is a super-2 number, since 2×21952831² = 963853577829122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21952793 and 21952802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21952811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 645655 + ... + 645688.

It is an arithmetic number, because the mean of its divisors is an integer number (5811048).

Almost surely, 2^21952831 is an apocalyptic number.

21952831 is a deficient number, since it is larger than the sum of its proper divisors (1291361).

21952831 is a wasteful number, since it uses less digits than its factorization.

21952831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1291360.

The product of its digits is 4320, while the sum is 31.

The square root of 21952831 is about 4685.3848294457. The cubic root of 21952831 is about 280.0035331187.

The spelling of 21952831 in words is "twenty-one million, nine hundred fifty-two thousand, eight hundred thirty-one".