28405973 has 4 divisors (see below), whose sum is σ = 29173740. Its totient is φ = 27638208.

The previous prime is 28405939. The next prime is 28406011. The reversal of 28405973 is 37950482.

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 13490929 + 14915044 = 3673^2 + 3862^2 .

It is a cyclic number.

It is not a de Polignac number, because 28405973 - 2²² = 24211669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28405903) 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 3 ways as a sum of consecutive naturals, for example, 383828 + ... + 383901.

It is an arithmetic number, because the mean of its divisors is an integer number (7293435).

Almost surely, 2^28405973 is an apocalyptic number.

It is an amenable number.

28405973 is a deficient number, since it is larger than the sum of its proper divisors (767767).

28405973 is an equidigital number, since it uses as much as digits as its factorization.

28405973 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 767766.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 28405973 is about 5329.7254150660. The cubic root of 28405973 is about 305.1194479736.

The spelling of 28405973 in words is "twenty-eight million, four hundred five thousand, nine hundred seventy-three".