221512134400 has 108 divisors (see below), whose sum is σ = 555788961952. Its totient is φ = 87390904320.

The previous prime is 221512134397. The next prime is 221512134479. The reversal of 221512134400 is 4431215122.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 230137 + ... + 704263.

Almost surely, 2^221512134400 is an apocalyptic number.

221512134400 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 221512134400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (277894480976).

221512134400 is an abundant number, since it is smaller than the sum of its proper divisors (334276827552).

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

221512134400 is an equidigital number, since it uses as much as digits as its factorization.

221512134400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474226 (or 474207 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

Adding to 221512134400 its reverse (4431215122), we get a palindrome (225943349522).

The spelling of 221512134400 in words is "two hundred twenty-one billion, five hundred twelve million, one hundred thirty-four thousand, four hundred".