28891939 has 2 divisors, whose sum is σ = 28891940. Its totient is φ = 28891938.

The previous prime is 28891927. The next prime is 28891957. The reversal of 28891939 is 93919882.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28891939 - 2¹⁷ = 28760867 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 28891892 and 28891901.

It is not a weakly prime, because it can be changed into another prime (28891999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14445969 + 14445970.

It is an arithmetic number, because the mean of its divisors is an integer number (14445970).

Almost surely, 2^28891939 is an apocalyptic number.

28891939 is a deficient number, since it is larger than the sum of its proper divisors (1).

28891939 is an equidigital number, since it uses as much as digits as its factorization.

28891939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 279936, while the sum is 49.

The square root of 28891939 is about 5375.1222311683. The cubic root of 28891939 is about 306.8496011294.

The spelling of 28891939 in words is "twenty-eight million, eight hundred ninety-one thousand, nine hundred thirty-nine".