28423521 has 32 divisors (see below), whose sum is σ = 48633600. Its totient is φ = 16070400.

The previous prime is 28423517. The next prime is 28423523. The reversal of 28423521 is 12532482.

It is not a de Polignac number, because 28423521 - 2² = 28423517 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (28423523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18345 + ... + 19833.

It is an arithmetic number, because the mean of its divisors is an integer number (1519800).

Almost surely, 2^28423521 is an apocalyptic number.

28423521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28423521 is a deficient number, since it is larger than the sum of its proper divisors (20210079).

28423521 is a wasteful number, since it uses less digits than its factorization.

28423521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1606 (or 1600 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 28423521 is about 5331.3713995557. The cubic root of 28423521 is about 305.1822649724.

The spelling of 28423521 in words is "twenty-eight million, four hundred twenty-three thousand, five hundred twenty-one".