21895951 has 16 divisors (see below), whose sum is σ = 28182528. Its totient is φ = 16509600.

The previous prime is 21895933. The next prime is 21895969. The reversal of 21895951 is 15959812.

It is an interprime number because it is at equal distance from previous prime (21895933) and next prime (21895969).

It is a cyclic number.

It is not a de Polignac number, because 21895951 - 2¹⁵ = 21863183 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21895921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2200 + ... + 6973.

It is an arithmetic number, because the mean of its divisors is an integer number (1761408).

Almost surely, 2^21895951 is an apocalyptic number.

21895951 is a deficient number, since it is larger than the sum of its proper divisors (6286577).

21895951 is a wasteful number, since it uses less digits than its factorization.

21895951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9222.

The product of its digits is 32400, while the sum is 40.

The square root of 21895951 is about 4679.3109535486. The cubic root of 21895951 is about 279.7614933240.

It can be divided in two parts, 218 and 95951, that added together give a palindrome (96169).

The spelling of 21895951 in words is "twenty-one million, eight hundred ninety-five thousand, nine hundred fifty-one".