28705457 has 4 divisors (see below), whose sum is σ = 31315056. Its totient is φ = 26095860.

The previous prime is 28705427. The next prime is 28705487. The reversal of 28705457 is 75450782.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (28705427) and next prime (28705487).

It is a cyclic number.

It is not a de Polignac number, because 28705457 - 2⁶ = 28705393 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28705457.

It is not an unprimeable number, because it can be changed into a prime (28705427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1304783 + ... + 1304804.

It is an arithmetic number, because the mean of its divisors is an integer number (7828764).

Almost surely, 2^28705457 is an apocalyptic number.

It is an amenable number.

28705457 is a deficient number, since it is larger than the sum of its proper divisors (2609599).

28705457 is a wasteful number, since it uses less digits than its factorization.

28705457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2609598.

The product of its (nonzero) digits is 78400, while the sum is 38.

The square root of 28705457 is about 5357.7473811295. The cubic root of 28705457 is about 306.1879923328.

The spelling of 28705457 in words is "twenty-eight million, seven hundred five thousand, four hundred fifty-seven".