40181591 has 4 divisors (see below), whose sum is σ = 42545232. Its totient is φ = 37817952.

The previous prime is 40181587. The next prime is 40181597. The reversal of 40181591 is 19518104.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 40181591 - 2² = 40181587 is a prime.

It is a super-2 number, since 2×40181591² = 3229120510582562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40181597) 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, 1181795 + ... + 1181828.

It is an arithmetic number, because the mean of its divisors is an integer number (10636308).

Almost surely, 2^40181591 is an apocalyptic number.

40181591 is a deficient number, since it is larger than the sum of its proper divisors (2363641).

40181591 is a wasteful number, since it uses less digits than its factorization.

40181591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363640.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 40181591 is about 6338.8950929953. The cubic root of 40181591 is about 342.5119352226.

Adding to 40181591 its reverse (19518104), we get a palindrome (59699695).

The spelling of 40181591 in words is "forty million, one hundred eighty-one thousand, five hundred ninety-one".