1321686861 has 32 divisors (see below), whose sum is σ = 1994803200. Its totient is φ = 771046080.

The previous prime is 1321686853. The next prime is 1321686887. The reversal of 1321686861 is 1686861231.

It is not a de Polignac number, because 1321686861 - 2³ = 1321686853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321686851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 341640 + ... + 345486.

It is an arithmetic number, because the mean of its divisors is an integer number (62337600).

Almost surely, 2^1321686861 is an apocalyptic number.

1321686861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321686861 is a deficient number, since it is larger than the sum of its proper divisors (673116339).

1321686861 is a wasteful number, since it uses less digits than its factorization.

1321686861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4249.

The product of its digits is 82944, while the sum is 42.

The square root of 1321686861 is about 36355.0114977289. The cubic root of 1321686861 is about 1097.4283896732.

The spelling of 1321686861 in words is "one billion, three hundred twenty-one million, six hundred eighty-six thousand, eight hundred sixty-one".