1221794280 has 192 divisors, whose sum is σ = 4706432640. Its totient is φ = 279251712.

The previous prime is 1221794263. The next prime is 1221794291. The reversal of 1221794280 is 824971221.

1221794280 is a `hidden beast` number, since 1 + 221 + 7 + 9 + 428 + 0 = 666.

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 47 ways as a sum of consecutive naturals, for example, 59062 + ... + 77018.

It is an arithmetic number, because the mean of its divisors is an integer number (24512670).

Almost surely, 2^1221794280 is an apocalyptic number.

1221794280 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 1221794280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2353216320).

1221794280 is an abundant number, since it is smaller than the sum of its proper divisors (3484638360).

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

1221794280 is a wasteful number, since it uses less digits than its factorization.

1221794280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17990 (or 17974 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 1221794280 is about 34954.1739996814. The cubic root of 1221794280 is about 1069.0533100347.

The spelling of 1221794280 in words is "one billion, two hundred twenty-one million, seven hundred ninety-four thousand, two hundred eighty".