20179980 has 36 divisors (see below), whose sum is σ = 61213152. Its totient is φ = 5381280.

The previous prime is 20179961. The next prime is 20179981. The reversal of 20179980 is 8997102.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (20179981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 55876 + ... + 56235.

Almost surely, 2^20179980 is an apocalyptic number.

20179980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20179980 is an abundant number, since it is smaller than the sum of its proper divisors (41033172).

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

20179980 is a wasteful number, since it uses less digits than its factorization.

20179980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112126 (or 112121 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 20179980 is about 4492.2132629696. The cubic root of 20179980 is about 272.2535661689.

The spelling of 20179980 in words is "twenty million, one hundred seventy-nine thousand, nine hundred eighty".