721668770439 has 4 divisors (see below), whose sum is σ = 962225027256. Its totient is φ = 481112513624.

The previous prime is 721668770413. The next prime is 721668770453. The reversal of 721668770439 is 934077866127.

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

It is a cyclic number.

It is not a de Polignac number, because 721668770439 - 2¹⁶ = 721668704903 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721668770479) 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, 120278128404 + ... + 120278128409.

It is an arithmetic number, because the mean of its divisors is an integer number (240556256814).

Almost surely, 2^721668770439 is an apocalyptic number.

721668770439 is a deficient number, since it is larger than the sum of its proper divisors (240556256817).

721668770439 is a wasteful number, since it uses less digits than its factorization.

721668770439 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240556256816.

The product of its (nonzero) digits is 21337344, while the sum is 60.

The spelling of 721668770439 in words is "seven hundred twenty-one billion, six hundred sixty-eight million, seven hundred seventy thousand, four hundred thirty-nine".