40181561 has 16 divisors (see below), whose sum is σ = 48524160. Its totient is φ = 32503680.

The previous prime is 40181551. The next prime is 40181563. The reversal of 40181561 is 16518104.

It is not a de Polignac number, because 40181561 - 2²² = 35987257 is a prime.

It is a super-2 number, since 2×40181561² = 3229115688793442, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 40181561.

It is not an unprimeable number, because it can be changed into a prime (40181563) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52421 + ... + 53181.

It is an arithmetic number, because the mean of its divisors is an integer number (3032760).

Almost surely, 2^40181561 is an apocalyptic number.

It is an amenable number.

40181561 is a deficient number, since it is larger than the sum of its proper divisors (8342599).

40181561 is a wasteful number, since it uses less digits than its factorization.

40181561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1184.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 40181561 is about 6338.8927266519. The cubic root of 40181561 is about 342.5118499816.

Adding to 40181561 its reverse (16518104), we get a palindrome (56699665).

The spelling of 40181561 in words is "forty million, one hundred eighty-one thousand, five hundred sixty-one".