1221355968680 has 16 divisors (see below), whose sum is σ = 2748050929620. Its totient is φ = 488542387456.

The previous prime is 1221355968673. The next prime is 1221355968761. The reversal of 1221355968680 is 868695531221.

It can be written as a sum of positive squares in 2 ways, for example, as 1125368775556 + 95987193124 = 1060834^2 + 309818^2 .

It is a super-2 number, since 2×1221355968680² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15266949569 + ... + 15266949648.

Almost surely, 2^{1221355968680} is an apocalyptic number.

1221355968680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221355968680 is an abundant number, since it is smaller than the sum of its proper divisors (1526694960940).

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

1221355968680 is a wasteful number, since it uses less digits than its factorization.

1221355968680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30533899228 (or 30533899224 counting only the distinct ones).

The product of its (nonzero) digits is 6220800, while the sum is 56.

The spelling of 1221355968680 in words is "one trillion, two hundred twenty-one billion, three hundred fifty-five million, nine hundred sixty-eight thousand, six hundred eighty".