21251612 has 24 divisors (see below), whose sum is σ = 38504592. Its totient is φ = 10256000.

The previous prime is 21251611. The next prime is 21251617. The reversal of 21251612 is 21615212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15923 + ... + 17205.

It is an arithmetic number, because the mean of its divisors is an integer number (1604358).

Almost surely, 2^21251612 is an apocalyptic number.

It is an amenable number.

21251612 is a deficient number, since it is larger than the sum of its proper divisors (17252980).

21251612 is a wasteful number, since it uses less digits than its factorization.

21251612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1429 (or 1427 counting only the distinct ones).

The product of its digits is 240, while the sum is 20.

The square root of 21251612 is about 4609.9470712797. The cubic root of 21251612 is about 276.9899165266.

Adding to 21251612 its reverse (21615212), we get a palindrome (42866824).

The spelling of 21251612 in words is "twenty-one million, two hundred fifty-one thousand, six hundred twelve".