1221022000 has 80 divisors (see below), whose sum is σ = 3220892064. Its totient is φ = 444000000.

The previous prime is 1221021931. The next prime is 1221022013. The reversal of 1221022000 is 2201221.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (10).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5751 + ... + 49750.

Almost surely, 2^1221022000 is an apocalyptic number.

1221022000 is a gapful number since it is divisible by the number (10) 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 1221022000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1610446032).

1221022000 is an abundant number, since it is smaller than the sum of its proper divisors (1999870064).

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

1221022000 is a wasteful number, since it uses less digits than its factorization.

1221022000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55535 (or 55519 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 1221022000 is about 34943.1252179882. The cubic root of 1221022000 is about 1068.8280177421.

Adding to 1221022000 its reverse (2201221), we get a palindrome (1223223221).

It can be divided in two parts, 12 and 21022000, that added together give a palindrome (21022012).

The spelling of 1221022000 in words is "one billion, two hundred twenty-one million, twenty-two thousand".