187561091 has 2 divisors, whose sum is σ = 187561092. Its totient is φ = 187561090.

The previous prime is 187561079. The next prime is 187561097. The reversal of 187561091 is 190165781.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-187561091 is a prime.

It is a super-2 number, since 2×187561091² = 70358325714220562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (187561097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93780545 + 93780546.

It is an arithmetic number, because the mean of its divisors is an integer number (93780546).

Almost surely, 2^187561091 is an apocalyptic number.

187561091 is a deficient number, since it is larger than the sum of its proper divisors (1).

187561091 is an equidigital number, since it uses as much as digits as its factorization.

187561091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 38.

The square root of 187561091 is about 13695.2944838729. The cubic root of 187561091 is about 572.4192760715.

The spelling of 187561091 in words is "one hundred eighty-seven million, five hundred sixty-one thousand, ninety-one".