13995991 has 2 divisors, whose sum is σ = 13995992. Its totient is φ = 13995990.

The previous prime is 13995977. The next prime is 13995997. The reversal of 13995991 is 19959931.

It is a strong prime.

It is an emirp because it is prime and its reverse (19959931) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13995991 - 2⁵ = 13995959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13995997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6997995 + 6997996.

It is an arithmetic number, because the mean of its divisors is an integer number (6997996).

Almost surely, 2^13995991 is an apocalyptic number.

13995991 is a deficient number, since it is larger than the sum of its proper divisors (1).

13995991 is an equidigital number, since it uses as much as digits as its factorization.

13995991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 98415, while the sum is 46.

The square root of 13995991 is about 3741.1216232569. The cubic root of 13995991 is about 240.9912188395.

It can be divided in two parts, 13 and 995991, that added together give a square (996004 = 998²).

The spelling of 13995991 in words is "thirteen million, nine hundred ninety-five thousand, nine hundred ninety-one".