28777557 has 4 divisors (see below), whose sum is σ = 38370080. Its totient is φ = 19185036.

The previous prime is 28777547. The next prime is 28777559. The reversal of 28777557 is 75577782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28777557 - 2¹⁰ = 28776533 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 (28777559) 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, 4796257 + ... + 4796262.

It is an arithmetic number, because the mean of its divisors is an integer number (9592520).

Almost surely, 2^28777557 is an apocalyptic number.

It is an amenable number.

28777557 is a deficient number, since it is larger than the sum of its proper divisors (9592523).

28777557 is an equidigital number, since it uses as much as digits as its factorization.

28777557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9592522.

The product of its digits is 960400, while the sum is 48.

The square root of 28777557 is about 5364.4717354088. The cubic root of 28777557 is about 306.4441305875. Note that the first 3 decimals are identical.

The spelling of 28777557 in words is "twenty-eight million, seven hundred seventy-seven thousand, five hundred fifty-seven".