21023012100 has 144 divisors (see below), whose sum is σ = 62114024448. Its totient is φ = 5488517760.

The previous prime is 21023012077. The next prime is 21023012117. The reversal of 21023012100 is 121032012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3353569 + ... + 3359831.

It is an arithmetic number, because the mean of its divisors is an integer number (431347392).

Almost surely, 2^21023012100 is an apocalyptic number.

21023012100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21023012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31057012224).

21023012100 is an abundant number, since it is smaller than the sum of its proper divisors (41091012348).

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

21023012100 is a wasteful number, since it uses less digits than its factorization.

21023012100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6514 (or 6507 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21023012100 its reverse (121032012), we get a palindrome (21144044112).

The spelling of 21023012100 in words is "twenty-one billion, twenty-three million, twelve thousand, one hundred".