15191861 has 2 divisors, whose sum is σ = 15191862. Its totient is φ = 15191860.

The previous prime is 15191837. The next prime is 15191879. The reversal of 15191861 is 16819151.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11600836 + 3591025 = 3406^2 + 1895^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15191861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15191881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7595930 + 7595931.

It is an arithmetic number, because the mean of its divisors is an integer number (7595931).

Almost surely, 2^15191861 is an apocalyptic number.

It is an amenable number.

15191861 is a deficient number, since it is larger than the sum of its proper divisors (1).

15191861 is an equidigital number, since it uses as much as digits as its factorization.

15191861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 32.

The square root of 15191861 is about 3897.6737934312. The cubic root of 15191861 is about 247.6682446164.

The spelling of 15191861 in words is "fifteen million, one hundred ninety-one thousand, eight hundred sixty-one".