1221877800 has 576 divisors, whose sum is σ = 4972181760. Its totient is φ = 264960000.

The previous prime is 1221877799. The next prime is 1221877817. The reversal of 1221877800 is 87781221.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 12097750 + ... + 12097850.

It is an arithmetic number, because the mean of its divisors is an integer number (8632260).

Almost surely, 2^1221877800 is an apocalyptic number.

1221877800 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 1221877800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2486090880).

1221877800 is an abundant number, since it is smaller than the sum of its proper divisors (3750303960).

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

1221877800 is a wasteful number, since it uses less digits than its factorization.

1221877800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194 (or 182 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The square root of 1221877800 is about 34955.3686863692. The cubic root of 1221877800 is about 1069.0776690995.

It can be divided in two parts, 12 and 21877800, that added together give a palindrome (21877812).

The spelling of 1221877800 in words is "one billion, two hundred twenty-one million, eight hundred seventy-seven thousand, eight hundred".