28611831 has 4 divisors (see below), whose sum is σ = 38149112. Its totient is φ = 19074552.

The previous prime is 28611823. The next prime is 28611851. The reversal of 28611831 is 13811682.

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

It is not a de Polignac number, because 28611831 - 2³ = 28611823 is a prime.

It is a super-2 number, since 2×28611831² = 1637273746345122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28611851) 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, 4768636 + ... + 4768641.

It is an arithmetic number, because the mean of its divisors is an integer number (9537278).

Almost surely, 2^28611831 is an apocalyptic number.

28611831 is a deficient number, since it is larger than the sum of its proper divisors (9537281).

28611831 is an equidigital number, since it uses as much as digits as its factorization.

28611831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9537280.

The product of its digits is 2304, while the sum is 30.

The square root of 28611831 is about 5349.0028042617. The cubic root of 28611831 is about 305.8547411720.

Subtracting from 28611831 its sum of digits (30), we obtain a square (28611801 = 5349²).

The spelling of 28611831 in words is "twenty-eight million, six hundred eleven thousand, eight hundred thirty-one".