1221432666 has 16 divisors (see below), whose sum is σ = 2443478304. Its totient is φ = 407042064.

The previous prime is 1221432661. The next prime is 1221432671. The reversal of 1221432666 is 6662341221.

It is an interprime number because it is at equal distance from previous prime (1221432661) and next prime (1221432671).

It is not an unprimeable number, because it can be changed into a prime (1221432661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2781 + ... + 49503.

It is an arithmetic number, because the mean of its divisors is an integer number (152717394).

Almost surely, 2^1221432666 is an apocalyptic number.

1221432666 is an abundant number, since it is smaller than the sum of its proper divisors (1222045638).

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

1221432666 is a wasteful number, since it uses less digits than its factorization.

1221432666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51085.

The product of its digits is 20736, while the sum is 33.

The square root of 1221432666 is about 34949.0009299265. Note that the first 3 decimals coincide. The cubic root of 1221432666 is about 1068.9478305239.

Adding to 1221432666 its reverse (6662341221), we get a palindrome (7883773887).

The spelling of 1221432666 in words is "one billion, two hundred twenty-one million, four hundred thirty-two thousand, six hundred sixty-six".