18561901 has 8 divisors (see below), whose sum is σ = 19679744. Its totient is φ = 17476560.

The previous prime is 18561869. The next prime is 18561923. The reversal of 18561901 is 10916581.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18561901 - 2⁵ = 18561869 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18561941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6945 + ... + 9238.

It is an arithmetic number, because the mean of its divisors is an integer number (2459968).

Almost surely, 2^18561901 is an apocalyptic number.

It is an amenable number.

18561901 is a deficient number, since it is larger than the sum of its proper divisors (1117843).

18561901 is a wasteful number, since it uses less digits than its factorization.

18561901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16251.

The product of its (nonzero) digits is 2160, while the sum is 31.

The square root of 18561901 is about 4308.3524693321. The cubic root of 18561901 is about 264.7732770668.

The spelling of 18561901 in words is "eighteen million, five hundred sixty-one thousand, nine hundred one".