18961580 has 48 divisors (see below), whose sum is σ = 44029440. Its totient is φ = 6801600.

The previous prime is 18961573. The next prime is 18961589. The reversal of 18961580 is 8516981.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (18961589) 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, 16835 + ... + 17925.

It is an arithmetic number, because the mean of its divisors is an integer number (917280).

Almost surely, 2^18961580 is an apocalyptic number.

18961580 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 18961580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22014720).

18961580 is an abundant number, since it is smaller than the sum of its proper divisors (25067860).

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

18961580 is a wasteful number, since it uses less digits than its factorization.

18961580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1190 (or 1188 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 18961580 is about 4354.4896371446. The cubic root of 18961580 is about 266.6601838702.

The spelling of 18961580 in words is "eighteen million, nine hundred sixty-one thousand, five hundred eighty".