1225312656 has 80 divisors (see below), whose sum is σ = 3203366400. Its totient is φ = 403569664.

The previous prime is 1225312643. The next prime is 1225312663. The reversal of 1225312656 is 6562135221.

It is a super-2 number, since 2×1225312656² = 3002782209907548672, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2557825 + ... + 2558303.

It is an arithmetic number, because the mean of its divisors is an integer number (40042080).

Almost surely, 2^1225312656 is an apocalyptic number.

1225312656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1225312656 is an abundant number, since it is smaller than the sum of its proper divisors (1978053744).

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

1225312656 is a wasteful number, since it uses less digits than its factorization.

1225312656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1016 (or 1010 counting only the distinct ones).

The product of its digits is 21600, while the sum is 33.

The square root of 1225312656 is about 35004.4662293257. The cubic root of 1225312656 is about 1070.0785035715.

Adding to 1225312656 its reverse (6562135221), we get a palindrome (7787447877).

The spelling of 1225312656 in words is "one billion, two hundred twenty-five million, three hundred twelve thousand, six hundred fifty-six".