1221663443 has 32 divisors (see below), whose sum is σ = 1673817600. Its totient is φ = 878683680.

The previous prime is 1221663439. The next prime is 1221663449. The reversal of 1221663443 is 3443661221.

It is not a de Polignac number, because 1221663443 - 2² = 1221663439 is a prime.

It is a super-2 number, since 2×1221663443² = 2984923135925228498, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221663449) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36596 + ... + 61502.

It is an arithmetic number, because the mean of its divisors is an integer number (52306800).

Almost surely, 2^1221663443 is an apocalyptic number.

1221663443 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1221663443 is a deficient number, since it is larger than the sum of its proper divisors (452154157).

1221663443 is a wasteful number, since it uses less digits than its factorization.

1221663443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24952 (or 24938 counting only the distinct ones).

The product of its digits is 20736, while the sum is 32.

The square root of 1221663443 is about 34952.3023991267. The cubic root of 1221663443 is about 1069.0151484764.

The spelling of 1221663443 in words is "one billion, two hundred twenty-one million, six hundred sixty-three thousand, four hundred forty-three".