6638978943 has 28 divisors (see below), whose sum is σ = 9975741048. Its totient is φ = 4416282000.

The previous prime is 6638978939. The next prime is 6638978959. The reversal of 6638978943 is 3498798366.

It is not a de Polignac number, because 6638978943 - 2² = 6638978939 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6638978963) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 330693 + ... + 350193.

It is an arithmetic number, because the mean of its divisors is an integer number (356276466).

Almost surely, 2^6638978943 is an apocalyptic number.

6638978943 is a deficient number, since it is larger than the sum of its proper divisors (3336762105).

6638978943 is an equidigital number, since it uses as much as digits as its factorization.

6638978943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19986 (or 19971 counting only the distinct ones).

The product of its digits is 47029248, while the sum is 63.

The square root of 6638978943 is about 81479.9296943732. The cubic root of 6638978943 is about 1879.4629278252.

The spelling of 6638978943 in words is "six billion, six hundred thirty-eight million, nine hundred seventy-eight thousand, nine hundred forty-three".