40679981 has 4 divisors (see below), whose sum is σ = 40724700. Its totient is φ = 40635264.

The previous prime is 40679971. The next prime is 40679987. The reversal of 40679981 is 18997604.

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 15015625 + 25664356 = 3875^2 + 5066^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40679981 is a prime.

It is a super-2 number, since 2×40679981² = 3309721708320722, 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 (40679987) 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, 20966 + ... + 22823.

It is an arithmetic number, because the mean of its divisors is an integer number (10181175).

Almost surely, 2^40679981 is an apocalyptic number.

It is an amenable number.

40679981 is a deficient number, since it is larger than the sum of its proper divisors (44719).

40679981 is an equidigital number, since it uses as much as digits as its factorization.

40679981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44718.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 40679981 is about 6378.0859981659. The cubic root of 40679981 is about 343.9222292417.

The spelling of 40679981 in words is "forty million, six hundred seventy-nine thousand, nine hundred eighty-one".