21053608 has 8 divisors (see below), whose sum is σ = 39475530. Its totient is φ = 10526800.

The previous prime is 21053597. The next prime is 21053609. The reversal of 21053608 is 80635012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 13089924 + 7963684 = 3618^2 + 2822^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (21053609) 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 as a sum of consecutive naturals, namely, 1315843 + ... + 1315858.

Almost surely, 2^21053608 is an apocalyptic number.

It is an amenable number.

21053608 is a deficient number, since it is larger than the sum of its proper divisors (18421922).

21053608 is a wasteful number, since it uses less digits than its factorization.

21053608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2631707 (or 2631703 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 21053608 is about 4588.4210791949. The cubic root of 21053608 is about 276.1269807078.

The spelling of 21053608 in words is "twenty-one million, fifty-three thousand, six hundred eight".