40399181 has 4 divisors (see below), whose sum is σ = 40424352. Its totient is φ = 40374012.

The previous prime is 40399159. The next prime is 40399217. The reversal of 40399181 is 18199304.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 40399181 - 2²² = 36204877 is a prime.

It is a super-2 number, since 2×40399181² = 3264187650941522, 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 (40399481) 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, 10001 + ... + 13446.

It is an arithmetic number, because the mean of its divisors is an integer number (10106088).

Almost surely, 2^40399181 is an apocalyptic number.

It is an amenable number.

40399181 is a deficient number, since it is larger than the sum of its proper divisors (25171).

40399181 is a wasteful number, since it uses less digits than its factorization.

40399181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25170.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 40399181 is about 6356.0350061969. The cubic root of 40399181 is about 343.1290756238.

The spelling of 40399181 in words is "forty million, three hundred ninety-nine thousand, one hundred eighty-one".