21625144 has 16 divisors (see below), whose sum is σ = 41061600. Its totient is φ = 10675392.

The previous prime is 21625117. The next prime is 21625181. The reversal of 21625144 is 44152612.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 16477 + ... + 17740.

It is an arithmetic number, because the mean of its divisors is an integer number (2566350).

Almost surely, 2^21625144 is an apocalyptic number.

It is an amenable number.

21625144 is a deficient number, since it is larger than the sum of its proper divisors (19436456).

21625144 is a wasteful number, since it uses less digits than its factorization.

21625144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34302 (or 34298 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 21625144 is about 4650.2842923847. The cubic root of 21625144 is about 278.6033511772.

Adding to 21625144 its reverse (44152612), we get a palindrome (65777756).

The spelling of 21625144 in words is "twenty-one million, six hundred twenty-five thousand, one hundred forty-four".