1221310644 has 24 divisors (see below), whose sum is σ = 2851427040. Its totient is φ = 406860384.

The previous prime is 1221310609. The next prime is 1221310681. The reversal of 1221310644 is 4460131221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8859 + ... + 50210.

It is an arithmetic number, because the mean of its divisors is an integer number (118809460).

Almost surely, 2^1221310644 is an apocalyptic number.

It is an amenable number.

1221310644 is an abundant number, since it is smaller than the sum of its proper divisors (1630116396).

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

1221310644 is a wasteful number, since it uses less digits than its factorization.

1221310644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60799 (or 60797 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 1221310644 is about 34947.2551711862. The cubic root of 1221310644 is about 1068.9122331199.

Adding to 1221310644 its reverse (4460131221), we get a palindrome (5681441865).

It can be divided in two parts, 12 and 21310644, that added together give a triangular number (21310656 = T₆₅₂₈).

The spelling of 1221310644 in words is "one billion, two hundred twenty-one million, three hundred ten thousand, six hundred forty-four".