21979534 has 8 divisors (see below), whose sum is σ = 32989320. Its totient is φ = 10983096.

The previous prime is 21979469. The next prime is 21979547. The reversal of 21979534 is 43597912.

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

It is a congruent number.

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, 4072 + ... + 7780.

It is an arithmetic number, because the mean of its divisors is an integer number (4123665).

Almost surely, 2^21979534 is an apocalyptic number.

21979534 is a deficient number, since it is larger than the sum of its proper divisors (11009786).

21979534 is a wasteful number, since it uses less digits than its factorization.

21979534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6674.

The product of its digits is 68040, while the sum is 40.

The square root of 21979534 is about 4688.2335692668. The cubic root of 21979534 is about 280.1170174159.

The spelling of 21979534 in words is "twenty-one million, nine hundred seventy-nine thousand, five hundred thirty-four".