21091136 has 28 divisors (see below), whose sum is σ = 45659040. Its totient is φ = 9586560.

The previous prime is 21091079. The next prime is 21091139. The reversal of 21091136 is 63119012.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21091139) 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, 14276 + ... + 15683.

It is an arithmetic number, because the mean of its divisors is an integer number (1630680).

Almost surely, 2^21091136 is an apocalyptic number.

It is an amenable number.

21091136 is an abundant number, since it is smaller than the sum of its proper divisors (24567904).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21091136 is a wasteful number, since it uses less digits than its factorization.

21091136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29982 (or 29972 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21091136 is about 4592.5086826265. The cubic root of 21091136 is about 276.2909485241.

The spelling of 21091136 in words is "twenty-one million, ninety-one thousand, one hundred thirty-six".