18661401 has 32 divisors (see below), whose sum is σ = 31756800. Its totient is φ = 10711440.

The previous prime is 18661387. The next prime is 18661417. The reversal of 18661401 is 10416681.

It is not a de Polignac number, because 18661401 - 2⁵ = 18661369 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (18661481) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3990 + ... + 7296.

It is an arithmetic number, because the mean of its divisors is an integer number (992400).

Almost surely, 2^18661401 is an apocalyptic number.

18661401 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18661401 is a deficient number, since it is larger than the sum of its proper divisors (13095399).

18661401 is a wasteful number, since it uses less digits than its factorization.

18661401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3346 (or 3340 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 18661401 is about 4319.8843734526. The cubic root of 18661401 is about 265.2455348605.

The spelling of 18661401 in words is "eighteen million, six hundred sixty-one thousand, four hundred one".