15978977291 has 2 divisors, whose sum is σ = 15978977292. Its totient is φ = 15978977290.

The previous prime is 15978977251. The next prime is 15978977299. The reversal of 15978977291 is 19277987951.

It is a strong prime.

It is an emirp because it is prime and its reverse (19277987951) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15978977291 - 2¹⁰ = 15978976267 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (15978977299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7989488645 + 7989488646.

It is an arithmetic number, because the mean of its divisors is an integer number (7989488646).

Almost surely, 2^15978977291 is an apocalyptic number.

15978977291 is a deficient number, since it is larger than the sum of its proper divisors (1).

15978977291 is an equidigital number, since it uses as much as digits as its factorization.

15978977291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20003760, while the sum is 65.

The spelling of 15978977291 in words is "fifteen billion, nine hundred seventy-eight million, nine hundred seventy-seven thousand, two hundred ninety-one".