40406381 has 2 divisors, whose sum is σ = 40406382. Its totient is φ = 40406380.

The previous prime is 40406329. The next prime is 40406383. The reversal of 40406381 is 18360404.

40406381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23522500 + 16883881 = 4850^2 + 4109^2 .

It is a cyclic number.

It is not a de Polignac number, because 40406381 - 2¹⁰ = 40405357 is a prime.

It is a super-2 number, since 2×40406381² = 3265351251034322, which contains 22 as substring.

Together with 40406383, 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 40406381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40406383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20203190 + 20203191.

It is an arithmetic number, because the mean of its divisors is an integer number (20203191).

Almost surely, 2^40406381 is an apocalyptic number.

It is an amenable number.

40406381 is a deficient number, since it is larger than the sum of its proper divisors (1).

40406381 is an equidigital number, since it uses as much as digits as its factorization.

40406381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 40406381 is about 6356.6013718024. The cubic root of 40406381 is about 343.1494587316.

Adding to 40406381 its reverse (18360404), we get a palindrome (58766785).

The spelling of 40406381 in words is "forty million, four hundred six thousand, three hundred eighty-one".