40128731 has 2 divisors, whose sum is σ = 40128732. Its totient is φ = 40128730.

The previous prime is 40128719. The next prime is 40128733. The reversal of 40128731 is 13782104.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40128731 is a prime.

It is a super-2 number, since 2×40128731² = 3220630103340722, which contains 22 as substring.

Together with 40128733, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 40128731.

It is not a weakly prime, because it can be changed into another prime (40128733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20064365 + 20064366.

It is an arithmetic number, because the mean of its divisors is an integer number (20064366).

Almost surely, 2^40128731 is an apocalyptic number.

40128731 is a deficient number, since it is larger than the sum of its proper divisors (1).

40128731 is an equidigital number, since it uses as much as digits as its factorization.

40128731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 40128731 is about 6334.7242244631. The cubic root of 40128731 is about 342.3616746552.

The spelling of 40128731 in words is "forty million, one hundred twenty-eight thousand, seven hundred thirty-one".