40251691 has 4 divisors (see below), whose sum is σ = 40383112. Its totient is φ = 40120272.

The previous prime is 40251677. The next prime is 40251703. The reversal of 40251691 is 19615204.

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 40251691 - 2¹³ = 40243499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40251611) 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, 65250 + ... + 65863.

It is an arithmetic number, because the mean of its divisors is an integer number (10095778).

Almost surely, 2^40251691 is an apocalyptic number.

40251691 is a deficient number, since it is larger than the sum of its proper divisors (131421).

40251691 is a wasteful number, since it uses less digits than its factorization.

40251691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131420.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 40251691 is about 6344.4220382947. The cubic root of 40251691 is about 342.7109993303.

Adding to 40251691 its reverse (19615204), we get a palindrome (59866895).

The spelling of 40251691 in words is "forty million, two hundred fifty-one thousand, six hundred ninety-one".