40656591 has 6 divisors (see below), whose sum is σ = 58726200. Its totient is φ = 27104388.

The previous prime is 40656569. The next prime is 40656607. The reversal of 40656591 is 19565604.

40656591 is a `hidden beast` number, since 4 + 0 + 6 + 565 + 91 = 666.

It is not a de Polignac number, because 40656591 - 2⁹ = 40656079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40656541) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2258691 + ... + 2258708.

It is an arithmetic number, because the mean of its divisors is an integer number (9787700).

Almost surely, 2^40656591 is an apocalyptic number.

40656591 is a deficient number, since it is larger than the sum of its proper divisors (18069609).

40656591 is a wasteful number, since it uses less digits than its factorization.

40656591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4517405 (or 4517402 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 40656591 is about 6376.2521123306. The cubic root of 40656591 is about 343.8563009644.

The spelling of 40656591 in words is "forty million, six hundred fifty-six thousand, five hundred ninety-one".