15951191881 has 2 divisors, whose sum is σ = 15951191882. Its totient is φ = 15951191880.

The previous prime is 15951191831. The next prime is 15951191911. The reversal of 15951191881 is 18819115951.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13442083600 + 2509108281 = 115940^2 + 50091^2 .

It is an emirp because it is prime and its reverse (18819115951) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15951191881 is a prime.

It is a super-2 number, since 2×15951191881² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15951191831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7975595940 + 7975595941.

It is an arithmetic number, because the mean of its divisors is an integer number (7975595941).

Almost surely, 2^15951191881 is an apocalyptic number.

It is an amenable number.

15951191881 is a deficient number, since it is larger than the sum of its proper divisors (1).

15951191881 is an equidigital number, since it uses as much as digits as its factorization.

15951191881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 49.

The spelling of 15951191881 in words is "fifteen billion, nine hundred fifty-one million, one hundred ninety-one thousand, eight hundred eighty-one".