39668681 has 8 divisors (see below), whose sum is σ = 42861000. Its totient is φ = 36496512.

The previous prime is 39668677. The next prime is 39668687. The reversal of 39668681 is 18686693.

It can be written as a sum of positive squares in 4 ways, for example, as 4752400 + 34916281 = 2180^2 + 5909^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 39668681 - 2² = 39668677 is a prime.

It is a super-2 number, since 2×39668681² = 3147208504559522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (39668687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 806 + ... + 8943.

It is an arithmetic number, because the mean of its divisors is an integer number (5357625).

Almost surely, 2^39668681 is an apocalyptic number.

It is an amenable number.

39668681 is a deficient number, since it is larger than the sum of its proper divisors (3192319).

39668681 is a wasteful number, since it uses less digits than its factorization.

39668681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10075.

The product of its digits is 373248, while the sum is 47.

The square root of 39668681 is about 6298.3077886048. The cubic root of 39668681 is about 341.0483243492.

The spelling of 39668681 in words is "thirty-nine million, six hundred sixty-eight thousand, six hundred eighty-one".