1221668631 has 24 divisors (see below), whose sum is σ = 1861816320. Its totient is φ = 769790736.

The previous prime is 1221668599. The next prime is 1221668639. The reversal of 1221668631 is 1368661221.

It is a happy number.

1221668631 is a `hidden beast` number, since 1 + 2 + 2 + 16 + 6 + 8 + 631 = 666.

It is not a de Polignac number, because 1221668631 - 2⁵ = 1221668599 is a prime.

It is a super-2 number, since 2×1221668631² = 2984948487938828322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221668639) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 67690 + ... + 83816.

It is an arithmetic number, because the mean of its divisors is an integer number (77575680).

Almost surely, 2^1221668631 is an apocalyptic number.

1221668631 is a deficient number, since it is larger than the sum of its proper divisors (640147689).

1221668631 is a wasteful number, since it uses less digits than its factorization.

1221668631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16595 (or 16592 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 1221668631 is about 34952.3766144736. The cubic root of 1221668631 is about 1069.0166617253.

The spelling of 1221668631 in words is "one billion, two hundred twenty-one million, six hundred sixty-eight thousand, six hundred thirty-one".