1213655256 has 192 divisors, whose sum is σ = 3687690240. Its totient is φ = 357504000.

The previous prime is 1213655251. The next prime is 1213655323. The reversal of 1213655256 is 6525563121.

1213655256 is a `hidden beast` number, since 1 + 21 + 36 + 552 + 56 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1213655256.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213655251) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6354121 + ... + 6354311.

It is an arithmetic number, because the mean of its divisors is an integer number (19206720).

Almost surely, 2^1213655256 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213655256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1843845120).

1213655256 is an abundant number, since it is smaller than the sum of its proper divisors (2474034984).

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

1213655256 is a wasteful number, since it uses less digits than its factorization.

1213655256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 391 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The square root of 1213655256 is about 34837.5552529164. Note that the first 3 decimals coincide. The cubic root of 1213655256 is about 1066.6741743395.

It can be divided in two parts, 121365 and 5256, that added together give a palindrome (126621).

The spelling of 1213655256 in words is "one billion, two hundred thirteen million, six hundred fifty-five thousand, two hundred fifty-six".