17979840 has 112 divisors (see below), whose sum is σ = 63459360. Its totient is φ = 4792320.

The previous prime is 17979809. The next prime is 17979887. The reversal of 17979840 is 4897971.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7600 + ... + 9680.

Almost surely, 2^17979840 is an apocalyptic number.

17979840 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 17979840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31729680).

17979840 is an abundant number, since it is smaller than the sum of its proper divisors (45479520).

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

17979840 is a wasteful number, since it uses less digits than its factorization.

17979840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2107 (or 2091 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 45.

The square root of 17979840 is about 4240.2641427156. The cubic root of 17979840 is about 261.9762618588.

The spelling of 17979840 in words is "seventeen million, nine hundred seventy-nine thousand, eight hundred forty".