40127991 has 4 divisors (see below), whose sum is σ = 53503992. Its totient is φ = 26751992.

The previous prime is 40127977. The next prime is 40128001. The reversal of 40127991 is 19972104.

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 40127991 - 2¹³ = 40119799 is a prime.

It is a super-2 number, since 2×40127991² = 3220511323392162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40127921) 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, 6687996 + ... + 6688001.

It is an arithmetic number, because the mean of its divisors is an integer number (13375998).

Almost surely, 2^40127991 is an apocalyptic number.

40127991 is a deficient number, since it is larger than the sum of its proper divisors (13376001).

40127991 is a wasteful number, since it uses less digits than its factorization.

40127991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13376000.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 40127991 is about 6334.6658159685. The cubic root of 40127991 is about 342.3595701847.

The spelling of 40127991 in words is "forty million, one hundred twenty-seven thousand, nine hundred ninety-one".