681008701021 has 4 divisors (see below), whose sum is σ = 742918582944. Its totient is φ = 619098819100.

The previous prime is 681008701013. The next prime is 681008701031. The reversal of 681008701021 is 120107800186.

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 a cyclic number.

It is not a de Polignac number, because 681008701021 - 2³ = 681008701013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681008701031) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30954940945 + ... + 30954940966.

It is an arithmetic number, because the mean of its divisors is an integer number (185729645736).

Almost surely, 2^681008701021 is an apocalyptic number.

It is an amenable number.

681008701021 is a deficient number, since it is larger than the sum of its proper divisors (61909881923).

681008701021 is a wasteful number, since it uses less digits than its factorization.

681008701021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61909881922.

The product of its (nonzero) digits is 5376, while the sum is 34.

The spelling of 681008701021 in words is "six hundred eighty-one billion, eight million, seven hundred one thousand, twenty-one".