2128638651 has 4 divisors (see below), whose sum is σ = 2838184872. Its totient is φ = 1419092432.

The previous prime is 2128638649. The next prime is 2128638671. The reversal of 2128638651 is 1568368212.

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

It is a cyclic number.

It is not a de Polignac number, because 2128638651 - 2¹ = 2128638649 is a prime.

It is a super-2 number, since 2×2128638651² = 9062205013062199602, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2128638671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354773106 + ... + 354773111.

It is an arithmetic number, because the mean of its divisors is an integer number (709546218).

Almost surely, 2^2128638651 is an apocalyptic number.

2128638651 is a deficient number, since it is larger than the sum of its proper divisors (709546221).

2128638651 is an equidigital number, since it uses as much as digits as its factorization.

2128638651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 709546220.

The product of its digits is 138240, while the sum is 42.

The square root of 2128638651 is about 46137.1721175020. The cubic root of 2128638651 is about 1286.3741805287.

The spelling of 2128638651 in words is "two billion, one hundred twenty-eight million, six hundred thirty-eight thousand, six hundred fifty-one".