18401861 has 4 divisors (see below), whose sum is σ = 19370400. Its totient is φ = 17433324.

The previous prime is 18401857. The next prime is 18401927. The reversal of 18401861 is 16810481.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16810481 = 2879 ⋅5839.

It is a cyclic number.

It is not a de Polignac number, because 18401861 - 2² = 18401857 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18401821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 484241 + ... + 484278.

It is an arithmetic number, because the mean of its divisors is an integer number (4842600).

Almost surely, 2^18401861 is an apocalyptic number.

It is an amenable number.

18401861 is a deficient number, since it is larger than the sum of its proper divisors (968539).

18401861 is an equidigital number, since it uses as much as digits as its factorization.

18401861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968538.

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 18401861 is about 4289.7390363517. The cubic root of 18401861 is about 264.0101245352.

The spelling of 18401861 in words is "eighteen million, four hundred one thousand, eight hundred sixty-one".