21155392 has 28 divisors (see below), whose sum is σ = 43338496. Its totient is φ = 10235520.

The previous prime is 21155371. The next prime is 21155399. The reversal of 21155392 is 29355112.

It is a super-2 number, since 2×21155392² = 895101221347328, 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 21155392.

It is not an unprimeable number, because it can be changed into a prime (21155399) 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, 3348 + ... + 7315.

Almost surely, 2^21155392 is an apocalyptic number.

It is an amenable number.

21155392 is an abundant number, since it is smaller than the sum of its proper divisors (22183104).

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

21155392 is a wasteful number, since it uses less digits than its factorization.

21155392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10706 (or 10696 counting only the distinct ones).

The product of its digits is 2700, while the sum is 28.

The square root of 21155392 is about 4599.4991031633. The cubic root of 21155392 is about 276.5712456213.

The spelling of 21155392 in words is "twenty-one million, one hundred fifty-five thousand, three hundred ninety-two".