28991332 has 12 divisors (see below), whose sum is σ = 50917356. Its totient is φ = 14443520.

The previous prime is 28991327. The next prime is 28991351. The reversal of 28991332 is 23319982.

It can be written as a sum of positive squares in 2 ways, for example, as 9771876 + 19219456 = 3126^2 + 4384^2 .

It is a super-2 number, since 2×28991332² = 1680994662268448, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28991291 and 28991300.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11773 + ... + 14020.

It is an arithmetic number, because the mean of its divisors is an integer number (4243113).

Almost surely, 2^28991332 is an apocalyptic number.

It is an amenable number.

28991332 is a deficient number, since it is larger than the sum of its proper divisors (21926024).

28991332 is a wasteful number, since it uses less digits than its factorization.

28991332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26078 (or 26076 counting only the distinct ones).

The product of its digits is 23328, while the sum is 37.

The square root of 28991332 is about 5384.3599433916. The cubic root of 28991332 is about 307.2010693548.

The spelling of 28991332 in words is "twenty-eight million, nine hundred ninety-one thousand, three hundred thirty-two".