1881616321 has 16 divisors (see below), whose sum is σ = 2197894608. Its totient is φ = 1594828800.

The previous prime is 1881616313. The next prime is 1881616327. The reversal of 1881616321 is 1236161881.

It can be written as a sum of positive squares in 8 ways, for example, as 460703296 + 1420913025 = 21464^2 + 37695^2 .

It is a cyclic number.

It is not a de Polignac number, because 1881616321 - 2³ = 1881616313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1881616327) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94770 + ... + 112891.

It is an arithmetic number, because the mean of its divisors is an integer number (137368413).

Almost surely, 2^1881616321 is an apocalyptic number.

It is an amenable number.

1881616321 is a deficient number, since it is larger than the sum of its proper divisors (316278287).

1881616321 is a wasteful number, since it uses less digits than its factorization.

1881616321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207732.

The product of its digits is 13824, while the sum is 37.

The square root of 1881616321 is about 43377.6016049758. The cubic root of 1881616321 is about 1234.5547567525.

The spelling of 1881616321 in words is "one billion, eight hundred eighty-one million, six hundred sixteen thousand, three hundred twenty-one".