781034721894 has 192 divisors, whose sum is σ = 2118109593600. Its totient is φ = 210713915808.

The previous prime is 781034721889. The next prime is 781034721917. The reversal of 781034721894 is 498127430187.

781034721894 is a `hidden beast` number, since 7 + 81 + 0 + 3 + 472 + 1 + 8 + 94 = 666.

It is a super-2 number, since 2×781034721894² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an alternating number because its digits alternate between odd and even.

It is a self number, because there is not a number n which added to its sum of digits gives 781034721894.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19824187 + ... + 19863545.

It is an arithmetic number, because the mean of its divisors is an integer number (11031820800).

Almost surely, 2^781034721894 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 781034721894, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059054796800).

781034721894 is an abundant number, since it is smaller than the sum of its proper divisors (1337074871706).

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

781034721894 is a wasteful number, since it uses less digits than its factorization.

781034721894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39709 (or 39697 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The spelling of 781034721894 in words is "seven hundred eighty-one billion, thirty-four million, seven hundred twenty-one thousand, eight hundred ninety-four".