1221292800 has 648 divisors, whose sum is σ = 5397092064. Its totient is φ = 256573440.

The previous prime is 1221292777. The next prime is 1221292819. The reversal of 1221292800 is 82921221.

It is a super-2 number, since 2×1221292800² = 2983112206663680000, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 5241484 + ... + 5241716.

Almost surely, 2^1221292800 is an apocalyptic number.

1221292800 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 1221292800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2698546032).

1221292800 is an abundant number, since it is smaller than the sum of its proper divisors (4175799264).

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

1221292800 is a wasteful number, since it uses less digits than its factorization.

1221292800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285 (or 263 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 1221292800 is about 34946.9998712336. Note that the first 3 decimals coincide. The cubic root of 1221292800 is about 1068.9070273019.

The spelling of 1221292800 in words is "one billion, two hundred twenty-one million, two hundred ninety-two thousand, eight hundred".