15977221499 has 2 divisors, whose sum is σ = 15977221500. Its totient is φ = 15977221498.

The previous prime is 15977221457. The next prime is 15977221523. The reversal of 15977221499 is 99412277951.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15977221499 is a prime.

It is not a weakly prime, because it can be changed into another prime (15977221439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7988610749 + 7988610750.

It is an arithmetic number, because the mean of its divisors is an integer number (7988610750).

Almost surely, 2^15977221499 is an apocalyptic number.

15977221499 is a deficient number, since it is larger than the sum of its proper divisors (1).

15977221499 is an equidigital number, since it uses as much as digits as its factorization.

15977221499 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2857680, while the sum is 56.

The spelling of 15977221499 in words is "fifteen billion, nine hundred seventy-seven million, two hundred twenty-one thousand, four hundred ninety-nine".