8721881021 has 8 divisors (see below), whose sum is σ = 9979421184. Its totient is φ = 7467230160.

The previous prime is 8721881009. The next prime is 8721881023. The reversal of 8721881021 is 1201881278.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8721881021 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 (8721881023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 715850 + ... + 727931.

It is an arithmetic number, because the mean of its divisors is an integer number (1247427648).

Almost surely, 2^8721881021 is an apocalyptic number.

It is an amenable number.

8721881021 is a deficient number, since it is larger than the sum of its proper divisors (1257540163).

8721881021 is a wasteful number, since it uses less digits than its factorization.

8721881021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1444651.

The product of its (nonzero) digits is 14336, while the sum is 38.

The square root of 8721881021 is about 93391.0114572061. The cubic root of 8721881021 is about 2058.4329223948.

The spelling of 8721881021 in words is "eight billion, seven hundred twenty-one million, eight hundred eighty-one thousand, twenty-one".