18641920 has 88 divisors (see below), whose sum is σ = 48931488. Its totient is φ = 6758400.

The previous prime is 18641899. The next prime is 18641923. The reversal of 18641920 is 2914681.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (88).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18641923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56155 + ... + 56485.

Almost surely, 2^18641920 is an apocalyptic number.

18641920 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 18641920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24465744).

18641920 is an abundant number, since it is smaller than the sum of its proper divisors (30289568).

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

18641920 is a wasteful number, since it uses less digits than its factorization.

18641920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367 (or 349 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 18641920 is about 4317.6289789652. The cubic root of 18641920 is about 265.1532043977.

The spelling of 18641920 in words is "eighteen million, six hundred forty-one thousand, nine hundred twenty".