681758781 has 32 divisors (see below), whose sum is σ = 1021206528. Its totient is φ = 400933440.

The previous prime is 681758761. The next prime is 681758807. The reversal of 681758781 is 187857186.

It is not a de Polignac number, because 681758781 - 2¹⁰ = 681757757 is a prime.

It is a super-2 number, since 2×681758781² = 929590070941211922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681758761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 789556 + ... + 790418.

It is an arithmetic number, because the mean of its divisors is an integer number (31912704).

Almost surely, 2^681758781 is an apocalyptic number.

It is an amenable number.

681758781 is a deficient number, since it is larger than the sum of its proper divisors (339447747).

681758781 is a wasteful number, since it uses less digits than its factorization.

681758781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1561.

The product of its digits is 752640, while the sum is 51.

The square root of 681758781 is about 26110.5109295088. The cubic root of 681758781 is about 880.1234249230.

The spelling of 681758781 in words is "six hundred eighty-one million, seven hundred fifty-eight thousand, seven hundred eighty-one".