79728351865 has 4 divisors (see below), whose sum is σ = 95674022244. Its totient is φ = 63782681488.

The previous prime is 79728351841. The next prime is 79728351881. The reversal of 79728351865 is 56815382797.

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 29162734441 + 50565617424 = 170771^2 + 224868^2 .

It is a cyclic number.

It is not a de Polignac number, because 79728351865 - 2³¹ = 77580868217 is a prime.

It is a super-2 number, since 2×79728351865² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7972835182 + ... + 7972835191.

It is an arithmetic number, because the mean of its divisors is an integer number (23918505561).

Almost surely, 2^79728351865 is an apocalyptic number.

It is an amenable number.

79728351865 is a deficient number, since it is larger than the sum of its proper divisors (15945670379).

79728351865 is a wasteful number, since it uses less digits than its factorization.

79728351865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15945670378.

The product of its digits is 25401600, while the sum is 61.

The spelling of 79728351865 in words is "seventy-nine billion, seven hundred twenty-eight million, three hundred fifty-one thousand, eight hundred sixty-five".