681102021 has 4 divisors (see below), whose sum is σ = 908136032. Its totient is φ = 454068012.

The previous prime is 681102017. The next prime is 681102029. The reversal of 681102021 is 120201186.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 681102021 - 2² = 681102017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681102029) 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 3 ways as a sum of consecutive naturals, for example, 113517001 + ... + 113517006.

It is an arithmetic number, because the mean of its divisors is an integer number (227034008).

Almost surely, 2^681102021 is an apocalyptic number.

It is an amenable number.

681102021 is a deficient number, since it is larger than the sum of its proper divisors (227034011).

681102021 is a wasteful number, since it uses less digits than its factorization.

681102021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227034010.

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 681102021 is about 26097.9313548028. The cubic root of 681102021 is about 879.8407171249.

The spelling of 681102021 in words is "six hundred eighty-one million, one hundred two thousand, twenty-one".