28405657 has 8 divisors (see below), whose sum is σ = 34373376. Its totient is φ = 22915392.

The previous prime is 28405639. The next prime is 28405673. The reversal of 28405657 is 75650482.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28405657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28405607) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119233 + ... + 119470.

It is an arithmetic number, because the mean of its divisors is an integer number (4296672).

Almost surely, 2^28405657 is an apocalyptic number.

It is an amenable number.

28405657 is a deficient number, since it is larger than the sum of its proper divisors (5967719).

28405657 is a wasteful number, since it uses less digits than its factorization.

28405657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238727.

The product of its (nonzero) digits is 67200, while the sum is 37.

The square root of 28405657 is about 5329.6957699291. The cubic root of 28405657 is about 305.1183165437.

The spelling of 28405657 in words is "twenty-eight million, four hundred five thousand, six hundred fifty-seven".