21388368 has 40 divisors (see below), whose sum is σ = 56751328. Its totient is φ = 6936192.

The previous prime is 21388333. The next prime is 21388373. The reversal of 21388368 is 86388312.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4246 + ... + 7797.

Almost surely, 2^21388368 is an apocalyptic number.

It is an amenable number.

21388368 is an abundant number, since it is smaller than the sum of its proper divisors (35362960).

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

21388368 is a wasteful number, since it uses less digits than its factorization.

21388368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12091 (or 12085 counting only the distinct ones).

The product of its digits is 55296, while the sum is 39.

The square root of 21388368 is about 4624.7559935633. The cubic root of 21388368 is about 277.5827981158.

The spelling of 21388368 in words is "twenty-one million, three hundred eighty-eight thousand, three hundred sixty-eight".