28321975 has 24 divisors (see below), whose sum is σ = 38591280. Its totient is φ = 20448000.

The previous prime is 28321973. The next prime is 28321991. The reversal of 28321975 is 57912382.

It is not a de Polignac number, because 28321975 - 2¹ = 28321973 is a prime.

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28321973) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49491 + ... + 50059.

It is an arithmetic number, because the mean of its divisors is an integer number (1607970).

Almost surely, 2^28321975 is an apocalyptic number.

28321975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28321975 is the 2845-th nonagonal number.

28321975 is a deficient number, since it is larger than the sum of its proper divisors (10269305).

28321975 is a wasteful number, since it uses less digits than its factorization.

28321975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771 (or 766 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 28321975 is about 5321.8394376381. The cubic root of 28321975 is about 304.8183994640.

It can be divided in two parts, 28 and 321975, that added together give a triangular number (322003 = T₈₀₂).

The spelling of 28321975 in words is "twenty-eight million, three hundred twenty-one thousand, nine hundred seventy-five".