1321687305 has 24 divisors (see below), whose sum is σ = 2328485640. Its totient is φ = 693342720.

The previous prime is 1321687271. The next prime is 1321687307. The reversal of 1321687305 is 5037861231.

It can be written as a sum of positive squares in 4 ways, for example, as 53187849 + 1268499456 = 7293^2 + 35616^2 .

It is not a de Polignac number, because 1321687305 - 2¹¹ = 1321685257 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1321687305.

It is not an unprimeable number, because it can be changed into a prime (1321687307) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 238000 + ... + 243489.

It is an arithmetic number, because the mean of its divisors is an integer number (97020235).

Almost surely, 2^1321687305 is an apocalyptic number.

1321687305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1321687305 is a deficient number, since it is larger than the sum of its proper divisors (1006798335).

1321687305 is a wasteful number, since it uses less digits than its factorization.

1321687305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 481561 (or 481558 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 1321687305 is about 36355.0176041767. The cubic root of 1321687305 is about 1097.4285125611.

The spelling of 1321687305 in words is "one billion, three hundred twenty-one million, six hundred eighty-seven thousand, three hundred five".