40391251 has 4 divisors (see below), whose sum is σ = 40412104. Its totient is φ = 40370400.

The previous prime is 40391231. The next prime is 40391257. The reversal of 40391251 is 15219304.

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 40391251 - 2⁷ = 40391123 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40391257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7185 + ... + 11506.

It is an arithmetic number, because the mean of its divisors is an integer number (10103026).

Almost surely, 2^40391251 is an apocalyptic number.

40391251 is a deficient number, since it is larger than the sum of its proper divisors (20853).

40391251 is a wasteful number, since it uses less digits than its factorization.

40391251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20852.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 40391251 is about 6355.4111590046. The cubic root of 40391251 is about 343.1066230925.

The spelling of 40391251 in words is "forty million, three hundred ninety-one thousand, two hundred fifty-one".