21291221109400 has 96 divisors (see below), whose sum is σ = 54536955594480. Its totient is φ = 7665606080000.

The previous prime is 21291221109391. The next prime is 21291221109413. The reversal of 21291221109400 is 490112219212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47687839 + ... + 48132238.

Almost surely, 2^{21291221109400} is an apocalyptic number.

21291221109400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21291221109400 is an abundant number, since it is smaller than the sum of its proper divisors (33245734485080).

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

21291221109400 is a wasteful number, since it uses less digits than its factorization.

21291221109400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95820205 (or 95820196 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

It can be divided in two parts, 212912 and 21109400, that added together give a palindrome (21322312).

The spelling of 21291221109400 in words is "twenty-one trillion, two hundred ninety-one billion, two hundred twenty-one million, one hundred nine thousand, four hundred".