19979539673 has 2 divisors, whose sum is σ = 19979539674. Its totient is φ = 19979539672.

The previous prime is 19979539627. The next prime is 19979539681. The reversal of 19979539673 is 37693597991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19155390409 + 824149264 = 138403^2 + 28708^2 .

It is a cyclic number.

It is not a de Polignac number, because 19979539673 - 2⁸ = 19979539417 is a prime.

It is not a weakly prime, because it can be changed into another prime (19979539603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989769836 + 9989769837.

It is an arithmetic number, because the mean of its divisors is an integer number (9989769837).

Almost surely, 2^19979539673 is an apocalyptic number.

It is an amenable number.

19979539673 is a deficient number, since it is larger than the sum of its proper divisors (1).

19979539673 is an equidigital number, since it uses as much as digits as its factorization.

19979539673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 86802030, while the sum is 68.

The spelling of 19979539673 in words is "nineteen billion, nine hundred seventy-nine million, five hundred thirty-nine thousand, six hundred seventy-three".