68481781 has 4 divisors (see below), whose sum is σ = 68742432. Its totient is φ = 68221132.

The previous prime is 68481689. The next prime is 68481793. The reversal of 68481781 is 18718486.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18718486 = 2 ⋅9359243.

It is a cyclic number.

It is not a de Polignac number, because 68481781 - 2⁷ = 68481653 is a prime.

It is a super-2 number, since 2×68481781² = 9379508657863922, 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 (68481481) 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, 129931 + ... + 130456.

It is an arithmetic number, because the mean of its divisors is an integer number (17185608).

Almost surely, 2^68481781 is an apocalyptic number.

It is an amenable number.

68481781 is a deficient number, since it is larger than the sum of its proper divisors (260651).

68481781 is a wasteful number, since it uses less digits than its factorization.

68481781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260650.

The product of its digits is 86016, while the sum is 43.

The square root of 68481781 is about 8275.3719553867. The cubic root of 68481781 is about 409.1271954510.

The spelling of 68481781 in words is "sixty-eight million, four hundred eighty-one thousand, seven hundred eighty-one".