21891781428000 has 384 divisors, whose sum is σ = 80056738105344. Its totient is φ = 5183676288000.

The previous prime is 21891781427983. The next prime is 21891781428007. The reversal of 21891781428000 is 82418719812.

It is not an unprimeable number, because it can be changed into a prime (21891781428007) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3747549 + ... + 7604451.

It is an arithmetic number, because the mean of its divisors is an integer number (208481088816).

Almost surely, 2^{21891781428000} is an apocalyptic number.

21891781428000 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 21891781428000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40028369052672).

21891781428000 is an abundant number, since it is smaller than the sum of its proper divisors (58164956677344).

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

21891781428000 is a wasteful number, since it uses less digits than its factorization.

21891781428000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3856985 (or 3856967 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 51.

The spelling of 21891781428000 in words is "twenty-one trillion, eight hundred ninety-one billion, seven hundred eighty-one million, four hundred twenty-eight thousand".