1321696656 has 320 divisors, whose sum is σ = 4677795840. Its totient is φ = 348986880.

The previous prime is 1321696643. The next prime is 1321696667. The reversal of 1321696656 is 6566961231.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2155806 + ... + 2156418.

It is an arithmetic number, because the mean of its divisors is an integer number (14618112).

Almost surely, 2^1321696656 is an apocalyptic number.

1321696656 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 1321696656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2338897920).

1321696656 is an abundant number, since it is smaller than the sum of its proper divisors (3356099184).

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

1321696656 is a wasteful number, since it uses less digits than its factorization.

1321696656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691 (or 679 counting only the distinct ones).

The product of its digits is 349920, while the sum is 45.

The square root of 1321696656 is about 36355.1462106811. The cubic root of 1321696656 is about 1097.4311006745.

The spelling of 1321696656 in words is "one billion, three hundred twenty-one million, six hundred ninety-six thousand, six hundred fifty-six".