187621261 has 2 divisors, whose sum is σ = 187621262. Its totient is φ = 187621260.

The previous prime is 187621249. The next prime is 187621267. The reversal of 187621261 is 162126781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 144456361 + 43164900 = 12019^2 + 6570^2 .

It is an emirp because it is prime and its reverse (162126781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 187621261 - 2⁵ = 187621229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (187621267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 93810630 + 93810631.

It is an arithmetic number, because the mean of its divisors is an integer number (93810631).

Almost surely, 2^187621261 is an apocalyptic number.

It is an amenable number.

187621261 is a deficient number, since it is larger than the sum of its proper divisors (1).

187621261 is an equidigital number, since it uses as much as digits as its factorization.

187621261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 34.

The square root of 187621261 is about 13697.4910476335. The cubic root of 187621261 is about 572.4804806373.

The spelling of 187621261 in words is "one hundred eighty-seven million, six hundred twenty-one thousand, two hundred sixty-one".