21222221001000 has 128 divisors (see below), whose sum is σ = 66231371381760. Its totient is φ = 5657716896000.

The previous prime is 21222221000983. The next prime is 21222221001019. The reversal of 21222221001000 is 10012222212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10069065 + ... + 11992935.

It is an arithmetic number, because the mean of its divisors is an integer number (517432588920).

Almost surely, 2^{21222221001000} is an apocalyptic number.

21222221001000 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 21222221001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33115685690880).

21222221001000 is an abundant number, since it is smaller than the sum of its proper divisors (45009150380760).

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

21222221001000 is a wasteful number, since it uses less digits than its factorization.

21222221001000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1927572 (or 1927558 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21222221001000 its reverse (10012222212), we get a palindrome (21232233223212).

The spelling of 21222221001000 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twenty-one million, one thousand".