20217930 has 64 divisors (see below), whose sum is σ = 53187840. Its totient is φ = 4895744.

The previous prime is 20217839. The next prime is 20217931. The reversal of 20217930 is 3971202.

It is a self number, because there is not a number n which added to its sum of digits gives 20217930.

It is not an unprimeable number, because it can be changed into a prime (20217931) 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, 14107 + ... + 15473.

It is an arithmetic number, because the mean of its divisors is an integer number (831060).

Almost surely, 2^20217930 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20217930, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26593920).

20217930 is an abundant number, since it is smaller than the sum of its proper divisors (32969910).

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

20217930 is a wasteful number, since it uses less digits than its factorization.

20217930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1423.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 20217930 is about 4496.4352547324. The cubic root of 20217930 is about 272.4241238681.

The spelling of 20217930 in words is "twenty million, two hundred seventeen thousand, nine hundred thirty".