21666470 has 16 divisors (see below), whose sum is σ = 44571168. Its totient is φ = 7428480.

The previous prime is 21666443. The next prime is 21666481. The reversal of 21666470 is 7466612.

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, 154691 + ... + 154830.

It is an arithmetic number, because the mean of its divisors is an integer number (2785698).

Almost surely, 2^21666470 is an apocalyptic number.

21666470 is an abundant number, since it is smaller than the sum of its proper divisors (22904698).

21666470 is a wasteful number, since it uses less digits than its factorization.

21666470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309535.

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 21666470 is about 4654.7255558196. The cubic root of 21666470 is about 278.7807100835.

The spelling of 21666470 in words is "twenty-one million, six hundred sixty-six thousand, four hundred seventy".