21121338 has 32 divisors (see below), whose sum is σ = 49944960. Its totient is φ = 5826240.

The previous prime is 21121333. The next prime is 21121349. The reversal of 21121338 is 83312112.

It is a super-2 number, since 2×21121338² = 892221837820488, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (21121333) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7453 + ... + 9888.

It is an arithmetic number, because the mean of its divisors is an integer number (1560780).

Almost surely, 2^21121338 is an apocalyptic number.

21121338 is an abundant number, since it is smaller than the sum of its proper divisors (28823622).

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

21121338 is a wasteful number, since it uses less digits than its factorization.

21121338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17382.

The product of its digits is 288, while the sum is 21.

The square root of 21121338 is about 4595.7956873647. The cubic root of 21121338 is about 276.4227662907.

The spelling of 21121338 in words is "twenty-one million, one hundred twenty-one thousand, three hundred thirty-eight".