67640081 has 4 divisors (see below), whose sum is σ = 67667892. Its totient is φ = 67612272.

The previous prime is 67640077. The next prime is 67640099. The reversal of 67640081 is 18004676.

67640081 = 5815² + 5816².

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 33814225 + 33825856 = 5815^2 + 5816^2 .

It is a cyclic number.

It is not a de Polignac number, because 67640081 - 2² = 67640077 is a prime.

It is a super-2 number, since 2×67640081² = 9150361115373122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67640381) 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, 9866 + ... + 15251.

It is an arithmetic number, because the mean of its divisors is an integer number (16916973).

Almost surely, 2^67640081 is an apocalyptic number.

67640081 is the 5816-th centered square number.

It is an amenable number.

67640081 is a deficient number, since it is larger than the sum of its proper divisors (27811).

67640081 is a wasteful number, since it uses less digits than its factorization.

67640081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27810.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 67640081 is about 8224.3590023782. The cubic root of 67640081 is about 407.4441058997. Note that the first 3 decimals are identical.

The spelling of 67640081 in words is "sixty-seven million, six hundred forty thousand, eighty-one".