21345424100 has 432 divisors, whose sum is σ = 64933094016. Its totient is φ = 5983488000.

The previous prime is 21345424097. The next prime is 21345424123. The reversal of 21345424100 is 142454312.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 21345424100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 28728329 + ... + 28729071.

It is an arithmetic number, because the mean of its divisors is an integer number (150308088).

Almost surely, 2^21345424100 is an apocalyptic number.

21345424100 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 21345424100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32466547008).

21345424100 is an abundant number, since it is smaller than the sum of its proper divisors (43587669916).

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

21345424100 is a wasteful number, since it uses less digits than its factorization.

21345424100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836 (or 822 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 21345424100 its reverse (142454312), we get a palindrome (21487878412).

The spelling of 21345424100 in words is "twenty-one billion, three hundred forty-five million, four hundred twenty-four thousand, one hundred".