21315044 has 6 divisors (see below), whose sum is σ = 37301334. Its totient is φ = 10657520.

The previous prime is 21315037. The next prime is 21315053. The reversal of 21315044 is 44051312.

It can be written as a sum of positive squares in only one way, i.e., 16080100 + 5234944 = 4010^2 + 2288^2 .

It is a super-2 number, since 2×21315044² = 908662201443872, which contains 22 as substring.

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 as a sum of consecutive naturals, namely, 2664377 + ... + 2664384.

It is an arithmetic number, because the mean of its divisors is an integer number (6216889).

Almost surely, 2^21315044 is an apocalyptic number.

It is an amenable number.

21315044 is a deficient number, since it is larger than the sum of its proper divisors (15986290).

21315044 is a wasteful number, since it uses less digits than its factorization.

21315044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5328765 (or 5328763 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21315044 is about 4616.8218505808. The cubic root of 21315044 is about 277.2652301085.

Adding to 21315044 its reverse (44051312), we get a palindrome (65366356).

The spelling of 21315044 in words is "twenty-one million, three hundred fifteen thousand, forty-four".