21030400100 has 72 divisors (see below), whose sum is σ = 46000258920. Its totient is φ = 8345272320.

The previous prime is 21030400073. The next prime is 21030400109. The reversal of 21030400100 is 100403012.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 3551444836 + 17478955264 = 59594^2 + 132208^2 .

It is not an unprimeable number, because it can be changed into a prime (21030400109) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7819556 + ... + 7822244.

It is an arithmetic number, because the mean of its divisors is an integer number (638892485).

Almost surely, 2^21030400100 is an apocalyptic number.

21030400100 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 21030400100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23000129460).

21030400100 is an abundant number, since it is smaller than the sum of its proper divisors (24969858820).

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

21030400100 is a wasteful number, since it uses less digits than its factorization.

21030400100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3297 (or 3290 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

Adding to 21030400100 its reverse (100403012), we get a palindrome (21130803112).

The spelling of 21030400100 in words is "twenty-one billion, thirty million, four hundred thousand, one hundred".