40389657 has 32 divisors (see below), whose sum is σ = 68428800. Its totient is φ = 20579520.

The previous prime is 40389581. The next prime is 40389691. The reversal of 40389657 is 75698304.

It is a happy number.

It is not a de Polignac number, because 40389657 - 2⁷ = 40389529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (40381657) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10594 + ... + 13892.

It is an arithmetic number, because the mean of its divisors is an integer number (2138400).

Almost surely, 2^40389657 is an apocalyptic number.

It is an amenable number.

40389657 is a deficient number, since it is larger than the sum of its proper divisors (28039143).

40389657 is a wasteful number, since it uses less digits than its factorization.

40389657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3373.

The product of its (nonzero) digits is 181440, while the sum is 42.

The square root of 40389657 is about 6355.2857528202. The cubic root of 40389657 is about 343.1021095808.

It can be divided in two parts, 4038 and 9657, that added together give a triangular number (13695 = T₁₆₅).

The spelling of 40389657 in words is "forty million, three hundred eighty-nine thousand, six hundred fifty-seven".