18860981 has 2 divisors, whose sum is σ = 18860982. Its totient is φ = 18860980.

The previous prime is 18860929. The next prime is 18860983. The reversal of 18860981 is 18906881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16072081 + 2788900 = 4009^2 + 1670^2 .

It is a cyclic number.

It is not a de Polignac number, because 18860981 - 2⁶ = 18860917 is a prime.

It is a super-2 number, since 2×18860981² = 711473208564722, which contains 22 as substring.

Together with 18860983, 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 (18860983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9430490 + 9430491.

It is an arithmetic number, because the mean of its divisors is an integer number (9430491).

Almost surely, 2^18860981 is an apocalyptic number.

It is an amenable number.

18860981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18860981 is an equidigital number, since it uses as much as digits as its factorization.

18860981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 18860981 is about 4342.9230939541. The cubic root of 18860981 is about 266.1877666857.

The spelling of 18860981 in words is "eighteen million, eight hundred sixty thousand, nine hundred eighty-one".