21503345400 has 240 divisors, whose sum is σ = 76423624200. Its totient is φ = 5600689920.

The previous prime is 21503345387. The next prime is 21503345417. The reversal of 21503345400 is 454330512.

21503345400 is a `hidden beast` number, since 215 + 0 + 3 + 3 + 45 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 681166 + ... + 712034.

Almost surely, 2^21503345400 is an apocalyptic number.

21503345400 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 21503345400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38211812100).

21503345400 is an abundant number, since it is smaller than the sum of its proper divisors (54920278800).

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

21503345400 is a wasteful number, since it uses less digits than its factorization.

21503345400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30940 (or 30922 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 27.

Adding to 21503345400 its reverse (454330512), we get a palindrome (21957675912).

The spelling of 21503345400 in words is "twenty-one billion, five hundred three million, three hundred forty-five thousand, four hundred".