28536421 has 4 divisors (see below), whose sum is σ = 30215052. Its totient is φ = 26857792.

The previous prime is 28536407. The next prime is 28536437. The reversal of 28536421 is 12463582.

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 11222500 + 17313921 = 3350^2 + 4161^2 .

It is a cyclic number.

It is not a de Polignac number, because 28536421 - 2⁷ = 28536293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28536481) 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, 839290 + ... + 839323.

It is an arithmetic number, because the mean of its divisors is an integer number (7553763).

Almost surely, 2^28536421 is an apocalyptic number.

It is an amenable number.

28536421 is a deficient number, since it is larger than the sum of its proper divisors (1678631).

28536421 is a wasteful number, since it uses less digits than its factorization.

28536421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1678630.

The product of its digits is 11520, while the sum is 31.

The square root of 28536421 is about 5341.9491760967. The cubic root of 28536421 is about 305.5857988259.

The spelling of 28536421 in words is "twenty-eight million, five hundred thirty-six thousand, four hundred twenty-one".