1221207056 has 40 divisors (see below), whose sum is σ = 2453128704. Its totient is φ = 588314880.

The previous prime is 1221207049. The next prime is 1221207061. The reversal of 1221207056 is 6507021221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110285 + ... + 120851.

Almost surely, 2^1221207056 is an apocalyptic number.

1221207056 is a gapful number since it is divisible by the number (16) 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 1221207056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1226564352).

1221207056 is an abundant number, since it is smaller than the sum of its proper divisors (1231921648).

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

1221207056 is a wasteful number, since it uses less digits than its factorization.

1221207056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10839 (or 10833 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 1221207056 is about 34945.7730777272. The cubic root of 1221207056 is about 1068.8820115948.

Adding to 1221207056 its reverse (6507021221), we get a palindrome (7728228277).

The spelling of 1221207056 in words is "one billion, two hundred twenty-one million, two hundred seven thousand, fifty-six".