857647749 has 16 divisors (see below), whose sum is σ = 1331551872. Its totient is φ = 480836928.

The previous prime is 857647733. The next prime is 857647757. The reversal of 857647749 is 947746758.

857647749 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 857647749 - 2⁴ = 857647733 is a prime.

It is a super-2 number, since 2×857647749² = 1471119322729534002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (857647249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 384174 + ... + 386399.

It is an arithmetic number, because the mean of its divisors is an integer number (83221992).

Almost surely, 2^857647749 is an apocalyptic number.

It is an amenable number.

857647749 is a deficient number, since it is larger than the sum of its proper divisors (473904123).

857647749 is a wasteful number, since it uses less digits than its factorization.

857647749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 770636.

The product of its digits is 11854080, while the sum is 57.

The square root of 857647749 is about 29285.6235890582. The cubic root of 857647749 is about 950.1007276390.

Subtracting 857647749 from its reverse (947746758), we obtain a palindrome (90099009).

The spelling of 857647749 in words is "eight hundred fifty-seven million, six hundred forty-seven thousand, seven hundred forty-nine".