321913681993 has 4 divisors (see below), whose sum is σ = 321934518468. Its totient is φ = 321892845520.

The previous prime is 321913681967. The next prime is 321913682003. The reversal of 321913681993 is 399186319123.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 214357888144 + 107555793849 = 462988^2 + 327957^2 .

It is a cyclic number.

It is not a de Polignac number, because 321913681993 - 2⁵ = 321913681961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (321913681913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10395046 + ... + 10425967.

It is an arithmetic number, because the mean of its divisors is an integer number (80483629617).

Almost surely, 2^321913681993 is an apocalyptic number.

It is an amenable number.

321913681993 is a deficient number, since it is larger than the sum of its proper divisors (20836475).

321913681993 is a wasteful number, since it uses less digits than its factorization.

321913681993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20836474.

The product of its digits is 1889568, while the sum is 55.

The spelling of 321913681993 in words is "three hundred twenty-one billion, nine hundred thirteen million, six hundred eighty-one thousand, nine hundred ninety-three".