187936981 has 2 divisors, whose sum is σ = 187936982. Its totient is φ = 187936980.

The previous prime is 187936963. The next prime is 187937027. The reversal of 187936981 is 189639781.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184036356 + 3900625 = 13566^2 + 1975^2 .

It is an emirp because it is prime and its reverse (189639781) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187936981 is a prime.

It is a super-2 number, since 2×187936981² = 70640617654788722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (187936081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93968490 + 93968491.

It is an arithmetic number, because the mean of its divisors is an integer number (93968491).

Almost surely, 2^187936981 is an apocalyptic number.

It is an amenable number.

187936981 is a deficient number, since it is larger than the sum of its proper divisors (1).

187936981 is an equidigital number, since it uses as much as digits as its factorization.

187936981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 52.

The square root of 187936981 is about 13709.0109417128. The cubic root of 187936981 is about 572.8014148585.

The spelling of 187936981 in words is "one hundred eighty-seven million, nine hundred thirty-six thousand, nine hundred eighty-one".