21002309974 has 4 divisors (see below), whose sum is σ = 31503464964. Its totient is φ = 10501154986.

The previous prime is 21002309941. The next prime is 21002309989. The reversal of 21002309974 is 47990320012.

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 (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250577492 + ... + 5250577495.

It is an arithmetic number, because the mean of its divisors is an integer number (7875866241).

Almost surely, 2^21002309974 is an apocalyptic number.

21002309974 is a deficient number, since it is larger than the sum of its proper divisors (10501154990).

21002309974 is a wasteful number, since it uses less digits than its factorization.

21002309974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10501154989.

The product of its (nonzero) digits is 27216, while the sum is 37.

Adding to 21002309974 its reverse (47990320012), we get a palindrome (68992629986).

The spelling of 21002309974 in words is "twenty-one billion, two million, three hundred nine thousand, nine hundred seventy-four".