1256117520 has 320 divisors, whose sum is σ = 4662558720. Its totient is φ = 273715200.

The previous prime is 1256117491. The next prime is 1256117521. The reversal of 1256117520 is 257116521.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (1256117521) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4634985 + ... + 4635255.

It is an arithmetic number, because the mean of its divisors is an integer number (14570496).

Almost surely, 2^1256117520 is an apocalyptic number.

1256117520 is a gapful number since it is divisible by the number (10) 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 1256117520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2331279360).

1256117520 is an abundant number, since it is smaller than the sum of its proper divisors (3406441200).

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

1256117520 is a wasteful number, since it uses less digits than its factorization.

1256117520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414 (or 408 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 1256117520 is about 35441.7482638766. The cubic root of 1256117520 is about 1078.9717923306.

Subtracting from 1256117520 its reverse (257116521), we obtain a palindrome (999000999).

The spelling of 1256117520 in words is "one billion, two hundred fifty-six million, one hundred seventeen thousand, five hundred twenty".