18121901 has 8 divisors (see below), whose sum is σ = 20826624. Its totient is φ = 15446160.

The previous prime is 18121891. The next prime is 18121921. The reversal of 18121901 is 10912181.

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

It is a cyclic number.

It is not a de Polignac number, because 18121901 - 2¹⁸ = 17859757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18121921) 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, 5885 + ... + 8418.

It is an arithmetic number, because the mean of its divisors is an integer number (2603328).

Almost surely, 2^18121901 is an apocalyptic number.

It is an amenable number.

18121901 is a deficient number, since it is larger than the sum of its proper divisors (2704723).

18121901 is a wasteful number, since it uses less digits than its factorization.

18121901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14491.

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 18121901 is about 4256.9826168308. The cubic root of 18121901 is about 262.6644218575.

It can be divided in two parts, 181 and 21901, that multiplied together give a square (3964081 = 1991²).

The spelling of 18121901 in words is "eighteen million, one hundred twenty-one thousand, nine hundred one".