20201820 has 48 divisors (see below), whose sum is σ = 59028480. Its totient is φ = 5152576.

The previous prime is 20201813. The next prime is 20201821. The reversal of 20201820 is 2810202.

It is a super-2 number, since 2×20201820² = 816227062624800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20201820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5940 + ... + 8699.

It is an arithmetic number, because the mean of its divisors is an integer number (1229760).

Almost surely, 2^20201820 is an apocalyptic number.

20201820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20201820 is an abundant number, since it is smaller than the sum of its proper divisors (38826660).

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

20201820 is a wasteful number, since it uses less digits than its factorization.

20201820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14674 (or 14672 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 20201820 is about 4494.6434786310. The cubic root of 20201820 is about 272.3517472065.

The spelling of 20201820 in words is "twenty million, two hundred one thousand, eight hundred twenty".