187999961 has 2 divisors, whose sum is σ = 187999962. Its totient is φ = 187999960.

The previous prime is 187999921. The next prime is 187999979. The reversal of 187999961 is 169999781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 160174336 + 27825625 = 12656^2 + 5275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187999961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 187999961.

It is not a weakly prime, because it can be changed into another prime (187999921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93999980 + 93999981.

It is an arithmetic number, because the mean of its divisors is an integer number (93999981).

Almost surely, 2^187999961 is an apocalyptic number.

It is an amenable number.

187999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

187999961 is an equidigital number, since it uses as much as digits as its factorization.

187999961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2204496, while the sum is 59.

The square root of 187999961 is about 13711.3077786183. The cubic root of 187999961 is about 572.8653919852.

The spelling of 187999961 in words is "one hundred eighty-seven million, nine hundred ninety-nine thousand, nine hundred sixty-one".