28701557 has 4 divisors (see below), whose sum is σ = 28723020. Its totient is φ = 28680096.

The previous prime is 28701551. The next prime is 28701601. The reversal of 28701557 is 75510782.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15928081 + 12773476 = 3991^2 + 3574^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28701557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28701551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8582 + ... + 11447.

It is an arithmetic number, because the mean of its divisors is an integer number (7180755).

Almost surely, 2^28701557 is an apocalyptic number.

It is an amenable number.

28701557 is a deficient number, since it is larger than the sum of its proper divisors (21463).

28701557 is a wasteful number, since it uses less digits than its factorization.

28701557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21462.

The product of its (nonzero) digits is 19600, while the sum is 35.

The square root of 28701557 is about 5357.3834098373. The cubic root of 28701557 is about 306.1741251988.

The spelling of 28701557 in words is "twenty-eight million, seven hundred one thousand, five hundred fifty-seven".