781749515556 has 243 divisors, whose sum is σ = 2129188423089. Its totient is φ = 241822937664.

The previous prime is 781749515501. The next prime is 781749515587. The reversal of 781749515556 is 655515947187.

It is a happy number.

The square root of 781749515556 is 884166.

It is a perfect power (a square), and thus also a powerful number.

781749515556 is a `hidden beast` number, since 7 + 8 + 1 + 74 + 9 + 5 + 1 + 5 + 556 = 666.

781749515556 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 91587337956 + 690162177600 = 302634^2 + 830760^2 .

It is a super-2 number, since 2×781749515556² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 781749515493 and 781749515502.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 5246640970 + ... + 5246641118.

Almost surely, 2^781749515556 is an apocalyptic number.

781749515556 is the 884166-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 781749515556

781749515556 is an abundant number, since it is smaller than the sum of its proper divisors (1347438907533).

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

781749515556 is a wasteful number, since it uses less digits than its factorization.

781749515556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440 (or 220 counting only the distinct ones).

The product of its digits is 52920000, while the sum is 63.

The spelling of 781749515556 in words is "seven hundred eighty-one billion, seven hundred forty-nine million, five hundred fifteen thousand, five hundred fifty-six".