1221531712 has 28 divisors (see below), whose sum is σ = 2458126656. Its totient is φ = 602161280.

The previous prime is 1221531697. The next prime is 1221531713. The reversal of 1221531712 is 2171351221.

It is not an unprimeable number, because it can be changed into a prime (1221531713) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129868 + ... + 138955.

Almost surely, 2^1221531712 is an apocalyptic number.

It is an amenable number.

1221531712 is an abundant number, since it is smaller than the sum of its proper divisors (1236594944).

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

1221531712 is an equidigital number, since it uses as much as digits as its factorization.

1221531712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268906 (or 268896 counting only the distinct ones).

The product of its digits is 840, while the sum is 25.

The square root of 1221531712 is about 34950.4179088033. The cubic root of 1221531712 is about 1068.9767234101.

Adding to 1221531712 its reverse (2171351221), we get a palindrome (3392882933).

The spelling of 1221531712 in words is "one billion, two hundred twenty-one million, five hundred thirty-one thousand, seven hundred twelve".