21869906 has 8 divisors (see below), whose sum is σ = 32824704. Its totient is φ = 10928340.

The previous prime is 21869879. The next prime is 21869951. The reversal of 21869906 is 60996812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 4871 + ... + 8213.

It is an arithmetic number, because the mean of its divisors is an integer number (4103088).

Almost surely, 2^21869906 is an apocalyptic number.

21869906 is a deficient number, since it is larger than the sum of its proper divisors (10954798).

21869906 is a wasteful number, since it uses less digits than its factorization.

21869906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6616.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 21869906 is about 4676.5271302538. The cubic root of 21869906 is about 279.6505248770.

The spelling of 21869906 in words is "twenty-one million, eight hundred sixty-nine thousand, nine hundred six".