20579940 has 96 divisors (see below), whose sum is σ = 66850560. Its totient is φ = 5246208.

The previous prime is 20579927. The next prime is 20579947. The reversal of 20579940 is 4997502.

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

It is a junction number, because it is equal to n+sod(n) for n = 20579895 and 20579904.

It is not an unprimeable number, because it can be changed into a prime (20579947) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11592 + ... + 13248.

It is an arithmetic number, because the mean of its divisors is an integer number (696360).

Almost surely, 2^20579940 is an apocalyptic number.

20579940 is a gapful number since it is divisible by the number (20) 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 20579940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33425280).

20579940 is an abundant number, since it is smaller than the sum of its proper divisors (46270620).

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

20579940 is a wasteful number, since it uses less digits than its factorization.

20579940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1698 (or 1690 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 20579940 is about 4536.5118758800. The cubic root of 20579940 is about 274.0404685640.

The spelling of 20579940 in words is "twenty million, five hundred seventy-nine thousand, nine hundred forty".