1321729816 has 32 divisors (see below), whose sum is σ = 2706670080. Its totient is φ = 600090400.

The previous prime is 1321729793. The next prime is 1321729841. The reversal of 1321729816 is 6189271231.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71925 + ... + 88411.

It is an arithmetic number, because the mean of its divisors is an integer number (84583440).

Almost surely, 2^1321729816 is an apocalyptic number.

It is an amenable number.

1321729816 is an abundant number, since it is smaller than the sum of its proper divisors (1384940264).

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

1321729816 is a wasteful number, since it uses less digits than its factorization.

1321729816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17415 (or 17411 counting only the distinct ones).

The product of its digits is 36288, while the sum is 40.

The square root of 1321729816 is about 36355.6022643003. The cubic root of 1321729816 is about 1097.4402784009.

It can be divided in two parts, 1321 and 729816, that added together give a palindrome (731137).

The spelling of 1321729816 in words is "one billion, three hundred twenty-one million, seven hundred twenty-nine thousand, eight hundred sixteen".