20402020 has 12 divisors (see below), whose sum is σ = 42844284. Its totient is φ = 8160800.

The previous prime is 20402017. The next prime is 20402021. The reversal of 20402020 is 2020402.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16305444 + 4096576 = 4038^2 + 2024^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 20401988 and 20402006.

It is not an unprimeable number, because it can be changed into a prime (20402021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 510031 + ... + 510070.

It is an arithmetic number, because the mean of its divisors is an integer number (3570357).

Almost surely, 2^20402020 is an apocalyptic number.

20402020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20402020 is an abundant number, since it is smaller than the sum of its proper divisors (22442264).

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

20402020 is a wasteful number, since it uses less digits than its factorization.

20402020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1020110 (or 1020108 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 10.

The square root of 20402020 is about 4516.8595284777. The cubic root of 20402020 is about 273.2484599992.

Adding to 20402020 its reverse (2020402), we get a palindrome (22422422).

It can be divided in two parts, 204020 and 20, that multiplied together give a square (4080400 = 2020²).

The spelling of 20402020 in words is "twenty million, four hundred two thousand, twenty".