21379906 has 8 divisors (see below), whose sum is σ = 32098320. Its totient is φ = 10680468.

The previous prime is 21379879. The next prime is 21379907. The reversal of 21379906 is 60997312.

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

It is not an unprimeable number, because it can be changed into a prime (21379907) 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 3 ways as a sum of consecutive naturals, for example, 1476 + ... + 6703.

It is an arithmetic number, because the mean of its divisors is an integer number (4012290).

Almost surely, 2^21379906 is an apocalyptic number.

21379906 is a deficient number, since it is larger than the sum of its proper divisors (10718414).

21379906 is a wasteful number, since it uses less digits than its factorization.

21379906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9488.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 21379906 is about 4623.8410439806. The cubic root of 21379906 is about 277.5461860739.

The spelling of 21379906 in words is "twenty-one million, three hundred seventy-nine thousand, nine hundred six".