18778428 has 36 divisors (see below), whose sum is σ = 49107240. Its totient is φ = 6043296.

The previous prime is 18778381. The next prime is 18778433. The reversal of 18778428 is 82487781.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7950 + ... + 10037.

It is an arithmetic number, because the mean of its divisors is an integer number (1364090).

Almost surely, 2^18778428 is an apocalyptic number.

18778428 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18778428 is an abundant number, since it is smaller than the sum of its proper divisors (30328812).

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

18778428 is a wasteful number, since it uses less digits than its factorization.

18778428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18026 (or 18021 counting only the distinct ones).

The product of its digits is 200704, while the sum is 45.

The square root of 18778428 is about 4333.4083583249. The cubic root of 18778428 is about 265.7988378659.

The spelling of 18778428 in words is "eighteen million, seven hundred seventy-eight thousand, four hundred twenty-eight".