18400961 has 2 divisors, whose sum is σ = 18400962. Its totient is φ = 18400960.

The previous prime is 18400939. The next prime is 18400969. The reversal of 18400961 is 16900481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18105025 + 295936 = 4255^2 + 544^2 .

It is a cyclic number.

It is not a de Polignac number, because 18400961 - 2¹⁰ = 18399937 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18400969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9200480 + 9200481.

It is an arithmetic number, because the mean of its divisors is an integer number (9200481).

Almost surely, 2^18400961 is an apocalyptic number.

It is an amenable number.

18400961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18400961 is an equidigital number, since it uses as much as digits as its factorization.

18400961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 18400961 is about 4289.6341335830. The cubic root of 18400961 is about 264.0058203874.

The spelling of 18400961 in words is "eighteen million, four hundred thousand, nine hundred sixty-one".