21670788 has 48 divisors (see below), whose sum is σ = 51891840. Its totient is φ = 7037184.

The previous prime is 21670787. The next prime is 21670813. The reversal of 21670788 is 88707612.

It is not an unprimeable number, because it can be changed into a prime (21670787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109906 + ... + 110102.

It is an arithmetic number, because the mean of its divisors is an integer number (1081080).

Almost surely, 2^21670788 is an apocalyptic number.

It is an amenable number.

21670788 is an abundant number, since it is smaller than the sum of its proper divisors (30221052).

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

21670788 is a wasteful number, since it uses less digits than its factorization.

21670788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 394 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 39.

The square root of 21670788 is about 4655.1893624213. The cubic root of 21670788 is about 278.7992286385.

The spelling of 21670788 in words is "twenty-one million, six hundred seventy thousand, seven hundred eighty-eight".