68428781 has 4 divisors (see below), whose sum is σ = 70020192. Its totient is φ = 66837372.

The previous prime is 68428753. The next prime is 68428793. The reversal of 68428781 is 18782486.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 68428781 - 2¹⁴ = 68412397 is a prime.

It is a super-2 number, since 2×68428781² = 9364996138291922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68428721) 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, 795641 + ... + 795726.

It is an arithmetic number, because the mean of its divisors is an integer number (17505048).

Almost surely, 2^68428781 is an apocalyptic number.

It is an amenable number.

68428781 is a deficient number, since it is larger than the sum of its proper divisors (1591411).

68428781 is a wasteful number, since it uses less digits than its factorization.

68428781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1591410.

The product of its digits is 172032, while the sum is 44.

The square root of 68428781 is about 8272.1690625857. The cubic root of 68428781 is about 409.0216231497.

The spelling of 68428781 in words is "sixty-eight million, four hundred twenty-eight thousand, seven hundred eighty-one".