28891861 has 2 divisors, whose sum is σ = 28891862. Its totient is φ = 28891860.

The previous prime is 28891847. The next prime is 28891871. The reversal of 28891861 is 16819882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28622500 + 269361 = 5350^2 + 519^2 .

It is a cyclic number.

It is not a de Polignac number, because 28891861 - 2²³ = 20503253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28891871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14445930 + 14445931.

It is an arithmetic number, because the mean of its divisors is an integer number (14445931).

Almost surely, 2^28891861 is an apocalyptic number.

It is an amenable number.

28891861 is a deficient number, since it is larger than the sum of its proper divisors (1).

28891861 is an equidigital number, since it uses as much as digits as its factorization.

28891861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 55296, while the sum is 43.

The square root of 28891861 is about 5375.1149755145. The cubic root of 28891861 is about 306.8493249937.

The spelling of 28891861 in words is "twenty-eight million, eight hundred ninety-one thousand, eight hundred sixty-one".