15991097 has 2 divisors, whose sum is σ = 15991098. Its totient is φ = 15991096.

The previous prime is 15991037. The next prime is 15991109. The reversal of 15991097 is 79019951.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12243001 + 3748096 = 3499^2 + 1936^2 .

It is an emirp because it is prime and its reverse (79019951) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15991097 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15991007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7995548 + 7995549.

It is an arithmetic number, because the mean of its divisors is an integer number (7995549).

Almost surely, 2^15991097 is an apocalyptic number.

It is an amenable number.

15991097 is a deficient number, since it is larger than the sum of its proper divisors (1).

15991097 is an equidigital number, since it uses as much as digits as its factorization.

15991097 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25515, while the sum is 41.

The square root of 15991097 is about 3998.8869701456. The cubic root of 15991097 is about 251.9374634861.

The spelling of 15991097 in words is "fifteen million, nine hundred ninety-one thousand, ninety-seven".