21312044 has 24 divisors (see below), whose sum is σ = 40360320. Its totient is φ = 9788544.

The previous prime is 21312023. The next prime is 21312059. The reversal of 21312044 is 44021312.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11237 + ... + 12995.

It is an arithmetic number, because the mean of its divisors is an integer number (1681680).

Almost surely, 2^21312044 is an apocalyptic number.

It is an amenable number.

21312044 is a deficient number, since it is larger than the sum of its proper divisors (19048276).

21312044 is a wasteful number, since it uses less digits than its factorization.

21312044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2009 (or 2007 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21312044 is about 4616.4969403217. The cubic root of 21312044 is about 277.2522215386.

Adding to 21312044 its reverse (44021312), we get a palindrome (65333356).

The spelling of 21312044 in words is "twenty-one million, three hundred twelve thousand, forty-four".