1321686366 has 128 divisors (see below), whose sum is σ = 3565126656. Its totient is φ = 315463680.

The previous prime is 1321686349. The next prime is 1321686407. The reversal of 1321686366 is 6636861231.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2023696 + ... + 2024348.

It is an arithmetic number, because the mean of its divisors is an integer number (27852552).

Almost surely, 2^1321686366 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1321686366, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1782563328).

1321686366 is an abundant number, since it is smaller than the sum of its proper divisors (2243440290).

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

1321686366 is a wasteful number, since it uses less digits than its factorization.

1321686366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026.

The product of its digits is 186624, while the sum is 42.

The square root of 1321686366 is about 36355.0046898635. The cubic root of 1321686366 is about 1097.4282526697.

The spelling of 1321686366 in words is "one billion, three hundred twenty-one million, six hundred eighty-six thousand, three hundred sixty-six".