20100020 has 24 divisors (see below), whose sum is σ = 43110144. Its totient is φ = 7868576.

The previous prime is 20099983. The next prime is 20100023. The reversal of 20100020 is 2000102.

It is a Harshad number since it is a multiple of its sum of digits (5).

It is a junction number, because it is equal to n+sod(n) for n = 20099977 and 20100013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20100023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9752 + ... + 11631.

It is an arithmetic number, because the mean of its divisors is an integer number (1796256).

Almost surely, 2^20100020 is an apocalyptic number.

20100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20100020 is an abundant number, since it is smaller than the sum of its proper divisors (23010124).

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

20100020 is a wasteful number, since it uses less digits than its factorization.

20100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21439 (or 21437 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 5.

The square root of 20100020 is about 4483.3045847901. The cubic root of 20100020 is about 271.8935028584.

Adding to 20100020 its reverse (2000102), we get a palindrome (22100122).

The spelling of 20100020 in words is "twenty million, one hundred thousand, twenty".