7981432721 has 8 divisors (see below), whose sum is σ = 8041800960. Its totient is φ = 7921095328.

The previous prime is 7981432717. The next prime is 7981432727. The reversal of 7981432721 is 1272341897.

7981432721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 7981432721 - 2² = 7981432717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7981432727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 988820 + ... + 996858.

It is an arithmetic number, because the mean of its divisors is an integer number (1005225120).

Almost surely, 2^7981432721 is an apocalyptic number.

It is an amenable number.

7981432721 is a deficient number, since it is larger than the sum of its proper divisors (60368239).

7981432721 is a wasteful number, since it uses less digits than its factorization.

7981432721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15423.

The product of its digits is 169344, while the sum is 44.

The square root of 7981432721 is about 89338.8645607274. The cubic root of 7981432721 is about 1998.4515281769.

The spelling of 7981432721 in words is "seven billion, nine hundred eighty-one million, four hundred thirty-two thousand, seven hundred twenty-one".