28891906 has 4 divisors (see below), whose sum is σ = 43337862. Its totient is φ = 14445952.

The previous prime is 28891903. The next prime is 28891927. The reversal of 28891906 is 60919882.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 19000881 + 9891025 = 4359^2 + 3145^2 .

It is not an unprimeable number, because it can be changed into a prime (28891903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7222975 + ... + 7222978.

Almost surely, 2^28891906 is an apocalyptic number.

28891906 is a deficient number, since it is larger than the sum of its proper divisors (14445956).

28891906 is a wasteful number, since it uses less digits than its factorization.

28891906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14445955.

The product of its (nonzero) digits is 62208, while the sum is 43.

The square root of 28891906 is about 5375.1191614698. The cubic root of 28891906 is about 306.8494843028.

The spelling of 28891906 in words is "twenty-eight million, eight hundred ninety-one thousand, nine hundred six".