28776557 has 2 divisors, whose sum is σ = 28776558. Its totient is φ = 28776556.

The previous prime is 28776551. The next prime is 28776569. The reversal of 28776557 is 75567782.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25745476 + 3031081 = 5074^2 + 1741^2 .

It is a cyclic number.

It is not a de Polignac number, because 28776557 - 2⁴ = 28776541 is a prime.

It is a super-3 number, since 3×28776557³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28776551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14388278 + 14388279.

It is an arithmetic number, because the mean of its divisors is an integer number (14388279).

Almost surely, 2^28776557 is an apocalyptic number.

It is an amenable number.

28776557 is a deficient number, since it is larger than the sum of its proper divisors (1).

28776557 is an equidigital number, since it uses as much as digits as its factorization.

28776557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 823200, while the sum is 47.

The square root of 28776557 is about 5364.3785287767. The cubic root of 28776557 is about 306.4405809733.

The spelling of 28776557 in words is "twenty-eight million, seven hundred seventy-six thousand, five hundred fifty-seven".