28208431 has 8 divisors (see below), whose sum is σ = 28857600. Its totient is φ = 27565080.

The previous prime is 28208429. The next prime is 28208443. The reversal of 28208431 is 13480282.

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

It is a cyclic number.

It is not a de Polignac number, because 28208431 - 2¹ = 28208429 is a prime.

It is a super-2 number, since 2×28208431² = 1591431158963522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28208431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28208231) 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, 9226 + ... + 11896.

It is an arithmetic number, because the mean of its divisors is an integer number (3607200).

Almost surely, 2^28208431 is an apocalyptic number.

28208431 is a deficient number, since it is larger than the sum of its proper divisors (649169).

28208431 is a wasteful number, since it uses less digits than its factorization.

28208431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2909.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 28208431 is about 5311.1609841917. The cubic root of 28208431 is about 304.4105105954.

The spelling of 28208431 in words is "twenty-eight million, two hundred eight thousand, four hundred thirty-one".