6642722381 has 4 divisors (see below), whose sum is σ = 6733718652. Its totient is φ = 6551726112.

The previous prime is 6642722353. The next prime is 6642722413. The reversal of 6642722381 is 1832272466.

6642722381 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4660246756 + 1982475625 = 68266^2 + 44525^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6642722381 is a prime.

It is a super-2 number, since 2×6642722381² = 88251521262076618322, which contains 22 as substring.

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 (6642722081) 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, 45498026 + ... + 45498171.

It is an arithmetic number, because the mean of its divisors is an integer number (1683429663).

Almost surely, 2^6642722381 is an apocalyptic number.

It is an amenable number.

6642722381 is a deficient number, since it is larger than the sum of its proper divisors (90996271).

6642722381 is an equidigital number, since it uses as much as digits as its factorization.

6642722381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90996270.

The product of its digits is 193536, while the sum is 41.

The square root of 6642722381 is about 81502.8979914211. The cubic root of 6642722381 is about 1879.8161112013.

The spelling of 6642722381 in words is "six billion, six hundred forty-two million, seven hundred twenty-two thousand, three hundred eighty-one".