28267993 has 4 divisors (see below), whose sum is σ = 30442468. Its totient is φ = 26093520.

The previous prime is 28267979. The next prime is 28267999. The reversal of 28267993 is 39976282.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14040009 + 14227984 = 3747^2 + 3772^2 .

It is a cyclic number.

It is not a de Polignac number, because 28267993 - 2⁵ = 28267961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28267999) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1087218 + ... + 1087243.

It is an arithmetic number, because the mean of its divisors is an integer number (7610617).

Almost surely, 2^28267993 is an apocalyptic number.

It is an amenable number.

28267993 is a deficient number, since it is larger than the sum of its proper divisors (2174475).

28267993 is a wasteful number, since it uses less digits than its factorization.

28267993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2174474.

The product of its digits is 326592, while the sum is 46.

The square root of 28267993 is about 5316.7652759925. The cubic root of 28267993 is about 304.6246138705.

The spelling of 28267993 in words is "twenty-eight million, two hundred sixty-seven thousand, nine hundred ninety-three".