15961391 has 2 divisors, whose sum is σ = 15961392. Its totient is φ = 15961390.

The previous prime is 15961381. The next prime is 15961399. The reversal of 15961391 is 19316951.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15961391 - 2²² = 11767087 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15961399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7980695 + 7980696.

It is an arithmetic number, because the mean of its divisors is an integer number (7980696).

Almost surely, 2^15961391 is an apocalyptic number.

15961391 is a deficient number, since it is larger than the sum of its proper divisors (1).

15961391 is an equidigital number, since it uses as much as digits as its factorization.

15961391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7290, while the sum is 35.

The square root of 15961391 is about 3995.1709600466. The cubic root of 15961391 is about 251.7813621807.

The spelling of 15961391 in words is "fifteen million, nine hundred sixty-one thousand, three hundred ninety-one".