68721520433 has 4 divisors (see below), whose sum is σ = 70018152948. Its totient is φ = 67424887920.

The previous prime is 68721520421. The next prime is 68721520459. The reversal of 68721520433 is 33402512786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 33402512786 = 2 ⋅16701256393.

It can be written as a sum of positive squares in 2 ways, for example, as 45408200464 + 23313319969 = 213092^2 + 152687^2 .

It is a cyclic number.

It is not a de Polignac number, because 68721520433 - 2¹⁰ = 68721519409 is a prime.

It is a super-3 number, since 3×68721520433³ (a number of 33 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68721523433) 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, 648316178 + ... + 648316283.

It is an arithmetic number, because the mean of its divisors is an integer number (17504538237).

Almost surely, 2^68721520433 is an apocalyptic number.

It is an amenable number.

68721520433 is a deficient number, since it is larger than the sum of its proper divisors (1296632515).

68721520433 is a wasteful number, since it uses less digits than its factorization.

68721520433 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1296632514.

The product of its (nonzero) digits is 241920, while the sum is 41.

The spelling of 68721520433 in words is "sixty-eight billion, seven hundred twenty-one million, five hundred twenty thousand, four hundred thirty-three".