21426172 has 12 divisors (see below), whose sum is σ = 38293920. Its totient is φ = 10485056.

The previous prime is 21426161. The next prime is 21426173. The reversal of 21426172 is 27162412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21426173) 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, 56797 + ... + 57172.

It is an arithmetic number, because the mean of its divisors is an integer number (3191160).

Almost surely, 2^21426172 is an apocalyptic number.

It is an amenable number.

21426172 is a deficient number, since it is larger than the sum of its proper divisors (16867748).

21426172 is a wasteful number, since it uses less digits than its factorization.

21426172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114020 (or 114018 counting only the distinct ones).

The product of its digits is 1344, while the sum is 25.

The square root of 21426172 is about 4628.8413237008. The cubic root of 21426172 is about 277.7462446457.

Adding to 21426172 its reverse (27162412), we get a palindrome (48588584).

The spelling of 21426172 in words is "twenty-one million, four hundred twenty-six thousand, one hundred seventy-two".