It is an unprimeable number.
Almost surely, 21256265636 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 1256265636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1546137600).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1256265636 is a wasteful number, since it uses less digits than its factorization.
1256265636 is an evil number, because the sum of its binary digits is even.
The square root of 1256265636 is about 35443.8377718892. The cubic root of 1256265636 is about 1079.0141999086.
The spelling of 1256265636 in words is "one billion, two hundred fifty-six million, two hundred sixty-five thousand, six hundred thirty-six".