21137936 has 20 divisors (see below), whose sum is σ = 43364412. Its totient is φ = 9947136.

The previous prime is 21137929. The next prime is 21137959. The reversal of 21137936 is 63973112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 13542400 + 7595536 = 3680^2 + 2756^2 .

It is an unprimeable number.

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, 38585 + ... + 39128.

Almost surely, 2^21137936 is an apocalyptic number.

It is an amenable number.

21137936 is an abundant number, since it is smaller than the sum of its proper divisors (22226476).

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

21137936 is a wasteful number, since it uses less digits than its factorization.

21137936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77738 (or 77732 counting only the distinct ones).

The product of its digits is 6804, while the sum is 32.

The square root of 21137936 is about 4597.6011136244. The cubic root of 21137936 is about 276.4951553880.

The spelling of 21137936 in words is "twenty-one million, one hundred thirty-seven thousand, nine hundred thirty-six".