21308974 has 4 divisors (see below), whose sum is σ = 31963464. Its totient is φ = 10654486.

The previous prime is 21308957. The next prime is 21308981. The reversal of 21308974 is 47980312.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5327242 + ... + 5327245.

It is an arithmetic number, because the mean of its divisors is an integer number (7990866).

Almost surely, 2^21308974 is an apocalyptic number.

21308974 is a deficient number, since it is larger than the sum of its proper divisors (10654490).

21308974 is a wasteful number, since it uses less digits than its factorization.

21308974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10654489.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 21308974 is about 4616.1644251478. The cubic root of 21308974 is about 277.2389081715.

The spelling of 21308974 in words is "twenty-one million, three hundred eight thousand, nine hundred seventy-four".