21053744 has 20 divisors (see below), whose sum is σ = 41661024. Its totient is φ = 10302528.

The previous prime is 21053741. The next prime is 21053783. The reversal of 21053744 is 44735012.

It is not an unprimeable number, because it can be changed into a prime (21053741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13247 + ... + 14750.

Almost surely, 2^21053744 is an apocalyptic number.

It is an amenable number.

21053744 is a deficient number, since it is larger than the sum of its proper divisors (20607280).

21053744 is a wasteful number, since it uses less digits than its factorization.

21053744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28052 (or 28046 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 26.

The square root of 21053744 is about 4588.4358990837. The cubic root of 21053744 is about 276.1275752724.

Adding to 21053744 its reverse (44735012), we get a palindrome (65788756).

The spelling of 21053744 in words is "twenty-one million, fifty-three thousand, seven hundred forty-four".