28691261 has 2 divisors, whose sum is σ = 28691262. Its totient is φ = 28691260.

The previous prime is 28691219. The next prime is 28691297. The reversal of 28691261 is 16219682.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24810361 + 3880900 = 4981^2 + 1970^2 .

It is a cyclic number.

It is not a de Polignac number, because 28691261 - 2²² = 24496957 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 (28691161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14345630 + 14345631.

It is an arithmetic number, because the mean of its divisors is an integer number (14345631).

Almost surely, 2^28691261 is an apocalyptic number.

It is an amenable number.

28691261 is a deficient number, since it is larger than the sum of its proper divisors (1).

28691261 is an equidigital number, since it uses as much as digits as its factorization.

28691261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 28691261 is about 5356.4224067935. The cubic root of 28691261 is about 306.1375099284.

The spelling of 28691261 in words is "twenty-eight million, six hundred ninety-one thousand, two hundred sixty-one".