15691261 has 2 divisors, whose sum is σ = 15691262. Its totient is φ = 15691260.

The previous prime is 15691253. The next prime is 15691271. The reversal of 15691261 is 16219651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11256025 + 4435236 = 3355^2 + 2106^2 .

It is a cyclic number.

It is not a de Polignac number, because 15691261 - 2³ = 15691253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15691211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7845630 + 7845631.

It is an arithmetic number, because the mean of its divisors is an integer number (7845631).

Almost surely, 2^15691261 is an apocalyptic number.

It is an amenable number.

15691261 is a deficient number, since it is larger than the sum of its proper divisors (1).

15691261 is an equidigital number, since it uses as much as digits as its factorization.

15691261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 31.

The square root of 15691261 is about 3961.2196354153. The cubic root of 15691261 is about 250.3528936300.

The spelling of 15691261 in words is "fifteen million, six hundred ninety-one thousand, two hundred sixty-one".