21021209974 has 4 divisors (see below), whose sum is σ = 31531814964. Its totient is φ = 10510604986.

The previous prime is 21021209969. The next prime is 21021209983. The reversal of 21021209974 is 47990212012.

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 polite number, since it can be written as a sum of consecutive naturals, namely, 5255302492 + ... + 5255302495.

It is an arithmetic number, because the mean of its divisors is an integer number (7882953741).

Almost surely, 2^21021209974 is an apocalyptic number.

21021209974 is a deficient number, since it is larger than the sum of its proper divisors (10510604990).

21021209974 is a wasteful number, since it uses less digits than its factorization.

21021209974 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10510604989.

The product of its (nonzero) digits is 18144, while the sum is 37.

The spelling of 21021209974 in words is "twenty-one billion, twenty-one million, two hundred nine thousand, nine hundred seventy-four".