21321974649 has 16 divisors (see below), whose sum is σ = 28668240000. Its totient is φ = 14095501056.

The previous prime is 21321974647. The next prime is 21321974701. The reversal of 21321974649 is 94647912312.

It is not a de Polignac number, because 21321974649 - 2¹ = 21321974647 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21321974598 and 21321974607.

It is not an unprimeable number, because it can be changed into a prime (21321974647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 227937 + ... + 307569.

It is an arithmetic number, because the mean of its divisors is an integer number (1791765000).

Almost surely, 2^21321974649 is an apocalyptic number.

It is an amenable number.

21321974649 is a deficient number, since it is larger than the sum of its proper divisors (7346265351).

21321974649 is a wasteful number, since it uses less digits than its factorization.

21321974649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80384.

The product of its digits is 653184, while the sum is 48.

The spelling of 21321974649 in words is "twenty-one billion, three hundred twenty-one million, nine hundred seventy-four thousand, six hundred forty-nine".