21979306 has 8 divisors (see below), whose sum is σ = 34402464. Its totient is φ = 10511820.

The previous prime is 21979297. The next prime is 21979319. The reversal of 21979306 is 60397912.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 238860 + ... + 238951.

It is an arithmetic number, because the mean of its divisors is an integer number (4300308).

Almost surely, 2^21979306 is an apocalyptic number.

21979306 is a deficient number, since it is larger than the sum of its proper divisors (12423158).

21979306 is a wasteful number, since it uses less digits than its factorization.

21979306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477836.

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

The square root of 21979306 is about 4688.2092530091. The cubic root of 21979306 is about 280.1160488345.

The spelling of 21979306 in words is "twenty-one million, nine hundred seventy-nine thousand, three hundred six".