18986580 has 72 divisors (see below), whose sum is σ = 57948072. Its totient is φ = 5031936.

The previous prime is 18986579. The next prime is 18986581. The reversal of 18986580 is 8568981.

It is an interprime number because it is at equal distance from previous prime (18986579) and next prime (18986581).

It can be written as a sum of positive squares in 4 ways, for example, as 427716 + 18558864 = 654^2 + 4308^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18986581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56172 + ... + 56508.

Almost surely, 2^18986580 is an apocalyptic number.

18986580 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 18986580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28974036).

18986580 is an abundant number, since it is smaller than the sum of its proper divisors (38961492).

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

18986580 is a wasteful number, since it uses less digits than its factorization.

18986580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The square root of 18986580 is about 4357.3592920483. The cubic root of 18986580 is about 266.7773256012. Note that the first 3 decimals are identical.

The spelling of 18986580 in words is "eighteen million, nine hundred eighty-six thousand, five hundred eighty".