21122712 has 48 divisors (see below), whose sum is σ = 61610640. Its totient is φ = 6499008.

The previous prime is 21122707. The next prime is 21122719. The reversal of 21122712 is 21722112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122719) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10348 + ... + 12219.

It is an arithmetic number, because the mean of its divisors is an integer number (1283555).

Almost surely, 2^21122712 is an apocalyptic number.

It is an amenable number.

21122712 is an abundant number, since it is smaller than the sum of its proper divisors (40487928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21122712 is a wasteful number, since it uses less digits than its factorization.

21122712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22592 (or 22585 counting only the distinct ones).

The product of its digits is 112, while the sum is 18.

The square root of 21122712 is about 4595.9451693857. The cubic root of 21122712 is about 276.4287601763.

Adding to 21122712 its reverse (21722112), we get a palindrome (42844824).

The spelling of 21122712 in words is "twenty-one million, one hundred twenty-two thousand, seven hundred twelve".