15999961 has 2 divisors, whose sum is σ = 15999962. Its totient is φ = 15999960.

The previous prime is 15999953. The next prime is 15999983. The reversal of 15999961 is 16999951.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9265936 + 6734025 = 3044^2 + 2595^2 .

It is a cyclic number.

It is not a de Polignac number, because 15999961 - 2³ = 15999953 is a prime.

It is not a weakly prime, because it can be changed into another prime (15999931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7999980 + 7999981.

It is an arithmetic number, because the mean of its divisors is an integer number (7999981).

Almost surely, 2^15999961 is an apocalyptic number.

It is an amenable number.

15999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

15999961 is an equidigital number, since it uses as much as digits as its factorization.

15999961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 196830, while the sum is 49.

The square root of 15999961 is about 3999.9951249970. The cubic root of 15999961 is about 251.9840052416.

The spelling of 15999961 in words is "fifteen million, nine hundred ninety-nine thousand, nine hundred sixty-one".