19927399621 has 16 divisors (see below), whose sum is σ = 20307139200. Its totient is φ = 19550868480.

The previous prime is 19927399607. The next prime is 19927399627. The reversal of 19927399621 is 12699372991.

It is a cyclic number.

It is not a de Polignac number, because 19927399621 - 2⁷ = 19927399493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19927399627) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 15434986 + ... + 15436276.

It is an arithmetic number, because the mean of its divisors is an integer number (1269196200).

Almost surely, 2^19927399621 is an apocalyptic number.

It is an amenable number.

19927399621 is a deficient number, since it is larger than the sum of its proper divisors (379739579).

19927399621 is a wasteful number, since it uses less digits than its factorization.

19927399621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2316.

The product of its digits is 3306744, while the sum is 58.

The spelling of 19927399621 in words is "nineteen billion, nine hundred twenty-seven million, three hundred ninety-nine thousand, six hundred twenty-one".