18771864 has 64 divisors (see below), whose sum is σ = 50595840. Its totient is φ = 5786880.

The previous prime is 18771821. The next prime is 18771889. The reversal of 18771864 is 46817781.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16564 + ... + 17660.

It is an arithmetic number, because the mean of its divisors is an integer number (790560).

Almost surely, 2^18771864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18771864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25297920).

18771864 is an abundant number, since it is smaller than the sum of its proper divisors (31823976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18771864 is a wasteful number, since it uses less digits than its factorization.

18771864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1160 (or 1156 counting only the distinct ones).

The product of its digits is 75264, while the sum is 42.

The square root of 18771864 is about 4332.6509206258. The cubic root of 18771864 is about 265.7678642597.

It can be divided in two parts, 1877 and 1864, that added together give a triangular number (3741 = T₈₆).

The spelling of 18771864 in words is "eighteen million, seven hundred seventy-one thousand, eight hundred sixty-four".