21662670 has 32 divisors (see below), whose sum is σ = 52117632. Its totient is φ = 5762592.

The previous prime is 21662653. The next prime is 21662671. The reversal of 21662670 is 7626612.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21662671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18729 + ... + 19851.

It is an arithmetic number, because the mean of its divisors is an integer number (1628676).

Almost surely, 2^21662670 is an apocalyptic number.

21662670 is an abundant number, since it is smaller than the sum of its proper divisors (30454962).

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

21662670 is a wasteful number, since it uses less digits than its factorization.

21662670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21662670 is about 4654.3173505897. The cubic root of 21662670 is about 278.7644110335.

The spelling of 21662670 in words is "twenty-one million, six hundred sixty-two thousand, six hundred seventy".