20001220 has 24 divisors (see below), whose sum is σ = 42537600. Its totient is φ = 7898592.

The previous prime is 20001217. The next prime is 20001227. The reversal of 20001220 is 2210002.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20001227) 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, 4750 + ... + 7909.

It is an arithmetic number, because the mean of its divisors is an integer number (1772400).

Almost surely, 2^20001220 is an apocalyptic number.

20001220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20001220 is an abundant number, since it is smaller than the sum of its proper divisors (22536380).

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

20001220 is a wasteful number, since it uses less digits than its factorization.

20001220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12747 (or 12745 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 7.

The square root of 20001220 is about 4472.2723530662. The cubic root of 20001220 is about 271.4472808631.

Adding to 20001220 its reverse (2210002), we get a palindrome (22211222).

The spelling of 20001220 in words is "twenty million, one thousand, two hundred twenty".