15891397 has 2 divisors, whose sum is σ = 15891398. Its totient is φ = 15891396.

The previous prime is 15891377. The next prime is 15891431. The reversal of 15891397 is 79319851.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14737921 + 1153476 = 3839^2 + 1074^2 .

It is a cyclic number.

It is not a de Polignac number, because 15891397 - 2¹⁵ = 15858629 is a prime.

It is a super-2 number, since 2×15891397² = 505072997223218, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15891347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7945698 + 7945699.

It is an arithmetic number, because the mean of its divisors is an integer number (7945699).

Almost surely, 2^15891397 is an apocalyptic number.

It is an amenable number.

15891397 is a deficient number, since it is larger than the sum of its proper divisors (1).

15891397 is an equidigital number, since it uses as much as digits as its factorization.

15891397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 43.

The square root of 15891397 is about 3986.4015101342. The cubic root of 15891397 is about 251.4127851136.

The spelling of 15891397 in words is "fifteen million, eight hundred ninety-one thousand, three hundred ninety-seven".