21121936 has 20 divisors (see below), whose sum is σ = 44644464. Its totient is φ = 9600800.

The previous prime is 21121913. The next prime is 21121937. The reversal of 21121936 is 63912112.

It is a super-2 number, since 2×21121936² = 892272360776192, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121936.

It is not an unprimeable number, because it can be changed into a prime (21121937) 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, 59830 + ... + 60181.

Almost surely, 2^21121936 is an apocalyptic number.

It is an amenable number.

21121936 is an abundant number, since it is smaller than the sum of its proper divisors (23522528).

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

21121936 is a wasteful number, since it uses less digits than its factorization.

21121936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120030 (or 120024 counting only the distinct ones).

The product of its digits is 648, while the sum is 25.

The square root of 21121936 is about 4595.8607463673. The cubic root of 21121936 is about 276.4253750152.

The spelling of 21121936 in words is "twenty-one million, one hundred twenty-one thousand, nine hundred thirty-six".