18797220 has 144 divisors (see below), whose sum is σ = 63750960. Its totient is φ = 4451328.

The previous prime is 18797209. The next prime is 18797239. The reversal of 18797220 is 2279781.

It can be written as a sum of positive squares in 8 ways, for example, as 3305124 + 15492096 = 1818^2 + 3936^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 67722 + ... + 67998.

It is an arithmetic number, because the mean of its divisors is an integer number (442715).

Almost surely, 2^18797220 is an apocalyptic number.

18797220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18797220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31875480).

18797220 is an abundant number, since it is smaller than the sum of its proper divisors (44953740).

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

18797220 is a wasteful number, since it uses less digits than its factorization.

18797220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 18797220 is about 4335.5760862889. The cubic root of 18797220 is about 265.8874719539.

The spelling of 18797220 in words is "eighteen million, seven hundred ninety-seven thousand, two hundred twenty".