18721401 has 8 divisors (see below), whose sum is σ = 24989184. Its totient is φ = 12467280.

The previous prime is 18721399. The next prime is 18721421. The reversal of 18721401 is 10412781.

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

It is not a de Polignac number, because 18721401 - 2¹ = 18721399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18721421) 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, 391 + ... + 6131.

It is an arithmetic number, because the mean of its divisors is an integer number (3123648).

Almost surely, 2^18721401 is an apocalyptic number.

It is an amenable number.

18721401 is a deficient number, since it is larger than the sum of its proper divisors (6267783).

18721401 is a wasteful number, since it uses less digits than its factorization.

18721401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6831.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 18721401 is about 4326.8234306475. The cubic root of 18721401 is about 265.5295025752.

The spelling of 18721401 in words is "eighteen million, seven hundred twenty-one thousand, four hundred one".