781871616 has 200 divisors, whose sum is σ = 2473184340. Its totient is φ = 245071872.

The previous prime is 781871609. The next prime is 781871617. The reversal of 781871616 is 616178187.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 756470016 + 25401600 = 27504^2 + 5040^2 .

It is a super-2 number, since 2×781871616² = 1222646447812902912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781871617) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 704470 + ... + 705578.

Almost surely, 2^781871616 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 781871616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1236592170).

781871616 is an abundant number, since it is smaller than the sum of its proper divisors (1691312724).

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

781871616 is a wasteful number, since it uses less digits than its factorization.

781871616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156 (or 1131 counting only the distinct ones).

The product of its digits is 112896, while the sum is 45.

The square root of 781871616 is about 27961.9673127625. The cubic root of 781871616 is about 921.2520822140.

The spelling of 781871616 in words is "seven hundred eighty-one million, eight hundred seventy-one thousand, six hundred sixteen".