28236431 has 4 divisors (see below), whose sum is σ = 28318152. Its totient is φ = 28154712.

The previous prime is 28236421. The next prime is 28236449. The reversal of 28236431 is 13463282.

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

It is a cyclic number.

It is not a de Polignac number, because 28236431 - 2⁶ = 28236367 is a prime.

It is a super-2 number, since 2×28236431² = 1594592071235522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28236394 and 28236403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28236421) 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, 40340 + ... + 41033.

It is an arithmetic number, because the mean of its divisors is an integer number (7079538).

Almost surely, 2^28236431 is an apocalyptic number.

28236431 is a deficient number, since it is larger than the sum of its proper divisors (81721).

28236431 is an equidigital number, since it uses as much as digits as its factorization.

28236431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81720.

The product of its digits is 6912, while the sum is 29.

The square root of 28236431 is about 5313.7962889068. The cubic root of 28236431 is about 304.5111976994.

The spelling of 28236431 in words is "twenty-eight million, two hundred thirty-six thousand, four hundred thirty-one".