1221222000 has 160 divisors (see below), whose sum is σ = 4044366144. Its totient is φ = 316800000.

The previous prime is 1221221999. The next prime is 1221222001. The reversal of 1221222000 is 2221221.

It is an interprime number because it is at equal distance from previous prime (1221221999) and next prime (1221222001).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221222001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 219250 + ... + 224750.

Almost surely, 2^1221222000 is an apocalyptic number.

1221222000 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 1221222000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2022183072).

1221222000 is an abundant number, since it is smaller than the sum of its proper divisors (2823144144).

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

1221222000 is a wasteful number, since it uses less digits than its factorization.

1221222000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5564 (or 5548 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 1221222000 is about 34945.9868940627. The cubic root of 1221222000 is about 1068.8863715728.

Adding to 1221222000 its reverse (2221221), we get a palindrome (1223443221).

The spelling of 1221222000 in words is "one billion, two hundred twenty-one million, two hundred twenty-two thousand".