15511978819 has 2 divisors, whose sum is σ = 15511978820. Its totient is φ = 15511978818.

The previous prime is 15511978793. The next prime is 15511978861. The reversal of 15511978819 is 91887911551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 15511978819 - 2²⁵ = 15478424387 is a prime.

It is a super-2 number, since 2×15511978819² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 15511978819.

It is not a weakly prime, because it can be changed into another prime (15511978319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7755989409 + 7755989410.

It is an arithmetic number, because the mean of its divisors is an integer number (7755989410).

Almost surely, 2^15511978819 is an apocalyptic number.

15511978819 is a deficient number, since it is larger than the sum of its proper divisors (1).

15511978819 is an equidigital number, since it uses as much as digits as its factorization.

15511978819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 55.

The spelling of 15511978819 in words is "fifteen billion, five hundred eleven million, nine hundred seventy-eight thousand, eight hundred nineteen".