21053804 has 6 divisors (see below), whose sum is σ = 36844164. Its totient is φ = 10526900.

The previous prime is 21053783. The next prime is 21053831. The reversal of 21053804 is 40835012.

It is a self number, because there is not a number n which added to its sum of digits gives 21053804.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2631722 + ... + 2631729.

It is an arithmetic number, because the mean of its divisors is an integer number (6140694).

Almost surely, 2^21053804 is an apocalyptic number.

It is an amenable number.

21053804 is a deficient number, since it is larger than the sum of its proper divisors (15790360).

21053804 is a wasteful number, since it uses less digits than its factorization.

21053804 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5263455 (or 5263453 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 21053804 is about 4588.4424372547. The cubic root of 21053804 is about 276.1278375795.

Adding to 21053804 its reverse (40835012), we get a palindrome (61888816).

The spelling of 21053804 in words is "twenty-one million, fifty-three thousand, eight hundred four".