21120836 has 12 divisors (see below), whose sum is σ = 40321680. Its totient is φ = 9600360.

The previous prime is 21120833. The next prime is 21120893. The reversal of 21120836 is 63802112.

It is not an unprimeable number, because it can be changed into a prime (21120833) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239966 + ... + 240053.

It is an arithmetic number, because the mean of its divisors is an integer number (3360140).

Almost surely, 2^21120836 is an apocalyptic number.

It is an amenable number.

21120836 is a deficient number, since it is larger than the sum of its proper divisors (19200844).

21120836 is a wasteful number, since it uses less digits than its factorization.

21120836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480034 (or 480032 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21120836 is about 4595.7410719056. The cubic root of 21120836 is about 276.4205763201.

Adding to 21120836 its reverse (63802112), we get a palindrome (84922948).

The spelling of 21120836 in words is "twenty-one million, one hundred twenty thousand, eight hundred thirty-six".