68479781 has 4 divisors (see below), whose sum is σ = 72084000. Its totient is φ = 64875564.

The previous prime is 68479777. The next prime is 68479783. The reversal of 68479781 is 18797486.

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 68479781 - 2² = 68479777 is a prime.

It is a super-2 number, since 2×68479781² = 9378960811615922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68479783) 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, 1802081 + ... + 1802118.

It is an arithmetic number, because the mean of its divisors is an integer number (18021000).

Almost surely, 2^68479781 is an apocalyptic number.

It is an amenable number.

68479781 is a deficient number, since it is larger than the sum of its proper divisors (3604219).

68479781 is a wasteful number, since it uses less digits than its factorization.

68479781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3604218.

The product of its digits is 677376, while the sum is 50.

The square root of 68479781 is about 8275.2511140146. The cubic root of 68479781 is about 409.1232125797.

The spelling of 68479781 in words is "sixty-eight million, four hundred seventy-nine thousand, seven hundred eighty-one".