28311557 has 2 divisors, whose sum is σ = 28311558. Its totient is φ = 28311556.

The previous prime is 28311553. The next prime is 28311571. The reversal of 28311557 is 75511382.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 6791236 = 4639^2 + 2606^2 .

It is a cyclic number.

It is not a de Polignac number, because 28311557 - 2² = 28311553 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28311553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14155778 + 14155779.

It is an arithmetic number, because the mean of its divisors is an integer number (14155779).

Almost surely, 2^28311557 is an apocalyptic number.

It is an amenable number.

28311557 is a deficient number, since it is larger than the sum of its proper divisors (1).

28311557 is an equidigital number, since it uses as much as digits as its factorization.

28311557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8400, while the sum is 32.

The square root of 28311557 is about 5320.8605507004. The cubic root of 28311557 is about 304.7810199200.

The spelling of 28311557 in words is "twenty-eight million, three hundred eleven thousand, five hundred fifty-seven".