321691613 has 6 divisors (see below), whose sum is σ = 327055482. Its totient is φ = 316414320.

The previous prime is 321691607. The next prime is 321691621. The reversal of 321691613 is 316196123.

321691613 = 12682² + 12683².

It can be written as a sum of positive squares in 3 ways, for example, as 54140164 + 267551449 = 7358^2 + 16357^2 .

It is not a de Polignac number, because 321691613 - 2¹⁴ = 321675229 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 321691613.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321691313) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 39506 + ... + 46947.

It is an arithmetic number, because the mean of its divisors is an integer number (54509247).

Almost surely, 2^321691613 is an apocalyptic number.

321691613 is the 12683-rd centered square number.

It is an amenable number.

321691613 is a deficient number, since it is larger than the sum of its proper divisors (5363869).

321691613 is an frugal number, since it uses more digits than its factorization.

321691613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86575 (or 86514 counting only the distinct ones).

The product of its digits is 5832, while the sum is 32.

The square root of 321691613 is about 17935.7635187354. The cubic root of 321691613 is about 685.1935184146.

The spelling of 321691613 in words is "three hundred twenty-one million, six hundred ninety-one thousand, six hundred thirteen".