21002100020 has 48 divisors (see below), whose sum is σ = 48192193728. Its totient is φ = 7624700160.

The previous prime is 21002100011. The next prime is 21002100029. The reversal of 21002100020 is 2000120012.

It is an interprime number because it is at equal distance from previous prime (21002100011) and next prime (21002100029).

It is a junction number, because it is equal to n+sod(n) for n = 21002099980 and 21002100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002100029) 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, 58379 + ... + 213101.

It is an arithmetic number, because the mean of its divisors is an integer number (1004004036).

Almost surely, 2^21002100020 is an apocalyptic number.

21002100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002100020 is an abundant number, since it is smaller than the sum of its proper divisors (27190093708).

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

21002100020 is a wasteful number, since it uses less digits than its factorization.

21002100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155360 (or 155358 counting only the distinct ones).

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

Adding to 21002100020 its reverse (2000120012), we get a palindrome (23002220032).

The spelling of 21002100020 in words is "twenty-one billion, two million, one hundred thousand, twenty".