21133688 has 32 divisors (see below), whose sum is σ = 41592960. Its totient is φ = 10047840.

The previous prime is 21133687. The next prime is 21133727. The reversal of 21133688 is 88633112.

It is a happy number.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60731 + ... + 61077.

It is an arithmetic number, because the mean of its divisors is an integer number (1299780).

Almost surely, 2^21133688 is an apocalyptic number.

It is an amenable number.

21133688 is a deficient number, since it is larger than the sum of its proper divisors (20459272).

21133688 is a wasteful number, since it uses less digits than its factorization.

21133688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 707 (or 703 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 21133688 is about 4597.1391103598. The cubic root of 21133688 is about 276.4766321334.

The spelling of 21133688 in words is "twenty-one million, one hundred thirty-three thousand, six hundred eighty-eight".