28988557 has 4 divisors (see below), whose sum is σ = 31218460. Its totient is φ = 26758656.

The previous prime is 28988551. The next prime is 28988563. The reversal of 28988557 is 75588982.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (28988551) and next prime (28988563).

It can be written as a sum of positive squares in 2 ways, for example, as 11964681 + 17023876 = 3459^2 + 4126^2 .

It is a cyclic number.

It is not a de Polignac number, because 28988557 - 2²³ = 20599949 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28988551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1114932 + ... + 1114957.

It is an arithmetic number, because the mean of its divisors is an integer number (7804615).

Almost surely, 2^28988557 is an apocalyptic number.

It is an amenable number.

28988557 is a deficient number, since it is larger than the sum of its proper divisors (2229903).

28988557 is a wasteful number, since it uses less digits than its factorization.

28988557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2229902.

The product of its digits is 1612800, while the sum is 52.

The square root of 28988557 is about 5384.1022464288. The cubic root of 28988557 is about 307.1912674576.

The spelling of 28988557 in words is "twenty-eight million, nine hundred eighty-eight thousand, five hundred fifty-seven".