19978233679 has 2 divisors, whose sum is σ = 19978233680. Its totient is φ = 19978233678.

The previous prime is 19978233641. The next prime is 19978233701. The reversal of 19978233679 is 97633287991.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19978233679 - 2²¹ = 19976136527 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19978233679.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19978237679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9989116839 + 9989116840.

It is an arithmetic number, because the mean of its divisors is an integer number (9989116840).

Almost surely, 2^19978233679 is an apocalyptic number.

19978233679 is a deficient number, since it is larger than the sum of its proper divisors (1).

19978233679 is an equidigital number, since it uses as much as digits as its factorization.

19978233679 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30862944, while the sum is 64.

The spelling of 19978233679 in words is "nineteen billion, nine hundred seventy-eight million, two hundred thirty-three thousand, six hundred seventy-nine".