20501220 has 24 divisors (see below), whose sum is σ = 57403584. Its totient is φ = 5466976.

The previous prime is 20501213. The next prime is 20501227. The reversal of 20501220 is 2210502.

It is an interprime number because it is at equal distance from previous prime (20501213) and next prime (20501227).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 20501196 and 20501205.

It is not an unprimeable number, because it can be changed into a prime (20501227) 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, 170784 + ... + 170903.

It is an arithmetic number, because the mean of its divisors is an integer number (2391816).

Almost surely, 2^20501220 is an apocalyptic number.

20501220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20501220 is an abundant number, since it is smaller than the sum of its proper divisors (36902364).

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

20501220 is a wasteful number, since it uses less digits than its factorization.

20501220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341699 (or 341697 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 12.

The square root of 20501220 is about 4527.8272935261. The cubic root of 20501220 is about 273.6906128342.

Adding to 20501220 its reverse (2210502), we get a palindrome (22711722).

The spelling of 20501220 in words is "twenty million, five hundred one thousand, two hundred twenty".