8043128007921 has 40 divisors (see below), whose sum is σ = 12403873785600. Its totient is φ = 5188592414880.

The previous prime is 8043128007913. The next prime is 8043128007989. The reversal of 8043128007921 is 1297008213408.

It is a happy number.

It is not a de Polignac number, because 8043128007921 - 2³ = 8043128007913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8043128007991) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 25604235 + ... + 25916463.

It is an arithmetic number, because the mean of its divisors is an integer number (310096844640).

Almost surely, 2^{8043128007921} is an apocalyptic number.

8043128007921 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

8043128007921 is a deficient number, since it is larger than the sum of its proper divisors (4360745777679).

8043128007921 is a wasteful number, since it uses less digits than its factorization.

8043128007921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322531 (or 322522 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 8043128007921 in words is "eight trillion, forty-three billion, one hundred twenty-eight million, seven thousand, nine hundred twenty-one".