18371261 has 2 divisors, whose sum is σ = 18371262. Its totient is φ = 18371260.

The previous prime is 18371257. The next prime is 18371263. The reversal of 18371261 is 16217381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14784025 + 3587236 = 3845^2 + 1894^2 .

It is an emirp because it is prime and its reverse (16217381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18371261 - 2² = 18371257 is a prime.

Together with 18371263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18371263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9185630 + 9185631.

It is an arithmetic number, because the mean of its divisors is an integer number (9185631).

Almost surely, 2^18371261 is an apocalyptic number.

It is an amenable number.

18371261 is a deficient number, since it is larger than the sum of its proper divisors (1).

18371261 is an equidigital number, since it uses as much as digits as its factorization.

18371261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016, while the sum is 29.

The square root of 18371261 is about 4286.1709018657. The cubic root of 18371261 is about 263.8637047082.

The spelling of 18371261 in words is "eighteen million, three hundred seventy-one thousand, two hundred sixty-one".