18861457 has 2 divisors, whose sum is σ = 18861458. Its totient is φ = 18861456.

The previous prime is 18861439. The next prime is 18861461. The reversal of 18861457 is 75416881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17313921 + 1547536 = 4161^2 + 1244^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18861457 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18861407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9430728 + 9430729.

It is an arithmetic number, because the mean of its divisors is an integer number (9430729).

Almost surely, 2^18861457 is an apocalyptic number.

It is an amenable number.

18861457 is a deficient number, since it is larger than the sum of its proper divisors (1).

18861457 is an equidigital number, since it uses as much as digits as its factorization.

18861457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 53760, while the sum is 40.

The square root of 18861457 is about 4342.9778954077. The cubic root of 18861457 is about 266.1900059525.

The spelling of 18861457 in words is "eighteen million, eight hundred sixty-one thousand, four hundred fifty-seven".