68457580021 has 4 divisors (see below), whose sum is σ = 68477524492. Its totient is φ = 68437635552.

The previous prime is 68457579989. The next prime is 68457580027. The reversal of 68457580021 is 12008575486.

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 41052432996 + 27405147025 = 202614^2 + 165545^2 .

It is a cyclic number.

It is not a de Polignac number, because 68457580021 - 2⁵ = 68457579989 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 (68457580027) 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, 9967086 + ... + 9973951.

It is an arithmetic number, because the mean of its divisors is an integer number (17119381123).

Almost surely, 2^68457580021 is an apocalyptic number.

It is an amenable number.

68457580021 is a deficient number, since it is larger than the sum of its proper divisors (19944471).

68457580021 is a wasteful number, since it uses less digits than its factorization.

68457580021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19944470.

The product of its (nonzero) digits is 537600, while the sum is 46.

The spelling of 68457580021 in words is "sixty-eight billion, four hundred fifty-seven million, five hundred eighty thousand, twenty-one".