781667542656 has 1920 divisors, whose sum is σ = 3243051060480. Its totient is φ = 181746892800.

The previous prime is 781667542633. The next prime is 781667542657. The reversal of 781667542656 is 656245766187.

781667542656 is a `hidden beast` number, since 7 + 81 + 6 + 6 + 7 + 542 + 6 + 5 + 6 = 666.

It is a super-2 number, since 2×781667542656² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 781667542593 and 781667542602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781667542657) by changing a digit.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 4680643885 + ... + 4680644051.

It is an arithmetic number, because the mean of its divisors is an integer number (1689089094).

Almost surely, 2^781667542656 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 781667542656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1621525530240).

781667542656 is an abundant number, since it is smaller than the sum of its proper divisors (2461383517824).

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

781667542656 is a wasteful number, since it uses less digits than its factorization.

781667542656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276 (or 244 counting only the distinct ones).

The product of its digits is 101606400, while the sum is 63.

The spelling of 781667542656 in words is "seven hundred eighty-one billion, six hundred sixty-seven million, five hundred forty-two thousand, six hundred fifty-six".