21669790 has 16 divisors (see below), whose sum is σ = 40060512. Its totient is φ = 8433504.

The previous prime is 21669787. The next prime is 21669797. The reversal of 21669790 is 9796612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21669797) 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, 28914 + ... + 29653.

It is an arithmetic number, because the mean of its divisors is an integer number (2503782).

Almost surely, 2^21669790 is an apocalyptic number.

21669790 is a deficient number, since it is larger than the sum of its proper divisors (18390722).

21669790 is a wasteful number, since it uses less digits than its factorization.

21669790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58611.

The product of its (nonzero) digits is 40824, while the sum is 40.

The square root of 21669790 is about 4655.0821689848. The cubic root of 21669790 is about 278.7949487464.

The spelling of 21669790 in words is "twenty-one million, six hundred sixty-nine thousand, seven hundred ninety".