857640240 has 240 divisors, whose sum is σ = 3078017280. Its totient is φ = 213373440.

The previous prime is 857640239. The next prime is 857640253. The reversal of 857640240 is 42046758.

857640240 is a `hidden beast` number, since 8 + 5 + 7 + 640 + 2 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 857640195 and 857640204.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 970839 + ... + 971721.

It is an arithmetic number, because the mean of its divisors is an integer number (12825072).

Almost surely, 2^857640240 is an apocalyptic number.

857640240 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 857640240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1539008640).

857640240 is an abundant number, since it is smaller than the sum of its proper divisors (2220377040).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

857640240 is a wasteful number, since it uses less digits than its factorization.

857640240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 992 (or 983 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 857640240 is about 29285.4953859415. The cubic root of 857640240 is about 950.0979548118.

Adding to 857640240 its reverse (42046758), we get a palindrome (899686998).

The spelling of 857640240 in words is "eight hundred fifty-seven million, six hundred forty thousand, two hundred forty".