721779349589 has 4 divisors (see below), whose sum is σ = 721783391724. Its totient is φ = 721775307456.

The previous prime is 721779349579. The next prime is 721779349591. The reversal of 721779349589 is 985943977127.

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 78045920689 + 643733428900 = 279367^2 + 802330^2 .

It is a cyclic number.

It is not a de Polignac number, because 721779349589 - 2¹⁶ = 721779284053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721779349579) 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, 1740212 + ... + 2114685.

It is an arithmetic number, because the mean of its divisors is an integer number (180445847931).

Almost surely, 2^721779349589 is an apocalyptic number.

It is an amenable number.

721779349589 is a deficient number, since it is larger than the sum of its proper divisors (4042135).

721779349589 is a wasteful number, since it uses less digits than its factorization.

721779349589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4042134.

The product of its digits is 240045120, while the sum is 71.

The spelling of 721779349589 in words is "seven hundred twenty-one billion, seven hundred seventy-nine million, three hundred forty-nine thousand, five hundred eighty-nine".