2638438656 has 144 divisors (see below), whose sum is σ = 8059312128. Its totient is φ = 750643200.

The previous prime is 2638438651. The next prime is 2638438679. The reversal of 2638438656 is 6568348362.

It is a super-2 number, since 2×2638438656² = 13922717082950172672, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 2638438599 and 2638438608.

It is not an unprimeable number, because it can be changed into a prime (2638438651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1455991 + ... + 1457801.

Almost surely, 2^2638438656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2638438656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4029656064).

2638438656 is an abundant number, since it is smaller than the sum of its proper divisors (5420873472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2638438656 is a wasteful number, since it uses less digits than its factorization.

2638438656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2108 (or 2094 counting only the distinct ones).

The product of its digits is 4976640, while the sum is 51.

The square root of 2638438656 is about 51365.7342593290. The cubic root of 2638438656 is about 1381.8121289418.

The spelling of 2638438656 in words is "two billion, six hundred thirty-eight million, four hundred thirty-eight thousand, six hundred fifty-six".