21504206974 has 4 divisors (see below), whose sum is σ = 32256310464. Its totient is φ = 10752103486.

The previous prime is 21504206959. The next prime is 21504206989. The reversal of 21504206974 is 47960240512.

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

It is an interprime number because it is at equal distance from previous prime (21504206959) and next prime (21504206989).

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 as a sum of consecutive naturals, namely, 5376051742 + ... + 5376051745.

It is an arithmetic number, because the mean of its divisors is an integer number (8064077616).

Almost surely, 2^21504206974 is an apocalyptic number.

21504206974 is a deficient number, since it is larger than the sum of its proper divisors (10752103490).

21504206974 is a wasteful number, since it uses less digits than its factorization.

21504206974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10752103489.

The product of its (nonzero) digits is 120960, while the sum is 40.

The spelling of 21504206974 in words is "twenty-one billion, five hundred four million, two hundred six thousand, nine hundred seventy-four".