15191987 has 2 divisors, whose sum is σ = 15191988. Its totient is φ = 15191986.

The previous prime is 15191971. The next prime is 15191993. The reversal of 15191987 is 78919151.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15191987 - 2⁴ = 15191971 is a prime.

It is not a weakly prime, because it can be changed into another prime (15191087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7595993 + 7595994.

It is an arithmetic number, because the mean of its divisors is an integer number (7595994).

Almost surely, 2^15191987 is an apocalyptic number.

15191987 is a deficient number, since it is larger than the sum of its proper divisors (1).

15191987 is an equidigital number, since it uses as much as digits as its factorization.

15191987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 41.

The square root of 15191987 is about 3897.6899568847. The cubic root of 15191987 is about 247.6689293276.

The spelling of 15191987 in words is "fifteen million, one hundred ninety-one thousand, nine hundred eighty-seven".