28031409 has 36 divisors (see below), whose sum is σ = 47918208. Its totient is φ = 15467760.

The previous prime is 28031407. The next prime is 28031417. The reversal of 28031409 is 90413082.

28031409 = 61² + 62² + ... + 438².

It is not a de Polignac number, because 28031409 - 2¹ = 28031407 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (28031401) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 60312 + ... + 60774.

Almost surely, 2^28031409 is an apocalyptic number.

It is an amenable number.

28031409 is a deficient number, since it is larger than the sum of its proper divisors (19886799).

28031409 is a wasteful number, since it uses less digits than its factorization.

28031409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538 (or 504 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 28031409 is about 5294.4696618264. The cubic root of 28031409 is about 303.7723978810.

The spelling of 28031409 in words is "twenty-eight million, thirty-one thousand, four hundred nine".