1221700620656 has 20 divisors (see below), whose sum is σ = 2367072651672. Its totient is φ = 610843162176.

The previous prime is 1221700620617. The next prime is 1221700620659. The reversal of 1221700620656 is 6560260071221.

It is a super-2 number, since 2×1221700620656² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221700620659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1132406 + ... + 1930218.

Almost surely, 2^{1221700620656} is an apocalyptic number.

1221700620656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1221700620656 is a deficient number, since it is larger than the sum of its proper divisors (1145372031016).

1221700620656 is an equidigital number, since it uses as much as digits as its factorization.

1221700620656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893528 (or 893522 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 38.

Adding to 1221700620656 its reverse (6560260071221), we get a palindrome (7781960691877).

The spelling of 1221700620656 in words is "one trillion, two hundred twenty-one billion, seven hundred million, six hundred twenty thousand, six hundred fifty-six".