681021081 has 32 divisors (see below), whose sum is σ = 1096744320. Its totient is φ = 415150272.

The previous prime is 681021067. The next prime is 681021091. The reversal of 681021081 is 180120186.

681021081 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 681021081 - 2⁷ = 681020953 is a prime.

It is a super-2 number, since 2×681021081² = 927579425532817122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (681021041) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28491 + ... + 46623.

It is an arithmetic number, because the mean of its divisors is an integer number (34273260).

Almost surely, 2^681021081 is an apocalyptic number.

It is an amenable number.

681021081 is a deficient number, since it is larger than the sum of its proper divisors (415723239).

681021081 is a wasteful number, since it uses less digits than its factorization.

681021081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18262 (or 18256 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 681021081 is about 26096.3806111116. The cubic root of 681021081 is about 879.8058632525.

The spelling of 681021081 in words is "six hundred eighty-one million, twenty-one thousand, eighty-one".