40161891 has 16 divisors (see below), whose sum is σ = 66763008. Its totient is φ = 20863200.

The previous prime is 40161889. The next prime is 40161959. The reversal of 40161891 is 19816104.

It is not a de Polignac number, because 40161891 - 2¹ = 40161889 is a prime.

It is a super-2 number, since 2×40161891² = 3225954977391762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (40161811) 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, 86700 + ... + 87161.

It is an arithmetic number, because the mean of its divisors is an integer number (4172688).

Almost surely, 2^40161891 is an apocalyptic number.

40161891 is a deficient number, since it is larger than the sum of its proper divisors (26601117).

40161891 is a wasteful number, since it uses less digits than its factorization.

40161891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173882.

The product of its (nonzero) digits is 1728, while the sum is 30.

The square root of 40161891 is about 6337.3410039227. The cubic root of 40161891 is about 342.4559511433.

Adding to 40161891 its reverse (19816104), we get a palindrome (59977995).

The spelling of 40161891 in words is "forty million, one hundred sixty-one thousand, eight hundred ninety-one".