18721371 has 16 divisors (see below), whose sum is σ = 25784064. Its totient is φ = 12073824.

The previous prime is 18721343. The next prime is 18721393. The reversal of 18721371 is 17312781.

It is not a de Polignac number, because 18721371 - 2²¹ = 16624219 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18721331) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24826 + ... + 25568.

It is an arithmetic number, because the mean of its divisors is an integer number (1611504).

Almost surely, 2^18721371 is an apocalyptic number.

18721371 is a deficient number, since it is larger than the sum of its proper divisors (7062693).

18721371 is a wasteful number, since it uses less digits than its factorization.

18721371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1010.

The product of its digits is 2352, while the sum is 30.

The square root of 18721371 is about 4326.8199638996. The cubic root of 18721371 is about 265.5293607430.

The spelling of 18721371 in words is "eighteen million, seven hundred twenty-one thousand, three hundred seventy-one".