18961680 has 120 divisors (see below), whose sum is σ = 61531776. Its totient is φ = 4828160.

The previous prime is 18961661. The next prime is 18961687. The reversal of 18961680 is 8616981.

It is a tau number, because it is divible by the number of its divisors (120).

It is not an unprimeable number, because it can be changed into a prime (18961687) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 403417 + ... + 403463.

Almost surely, 2^18961680 is an apocalyptic number.

18961680 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 18961680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30765888).

18961680 is an abundant number, since it is smaller than the sum of its proper divisors (42570096).

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

18961680 is a wasteful number, since it uses less digits than its factorization.

18961680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 18961680 is about 4354.5011195314. The cubic root of 18961680 is about 266.6606526421.

The spelling of 18961680 in words is "eighteen million, nine hundred sixty-one thousand, six hundred eighty".