2638928821 has 2 divisors, whose sum is σ = 2638928822. Its totient is φ = 2638928820.

The previous prime is 2638928767. The next prime is 2638928839. The reversal of 2638928821 is 1288298362.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1358291025 + 1280637796 = 36855^2 + 35786^2 .

It is a cyclic number.

It is not a de Polignac number, because 2638928821 - 2²¹ = 2636831669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2638928861) 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 as a sum of consecutive naturals, namely, 1319464410 + 1319464411.

It is an arithmetic number, because the mean of its divisors is an integer number (1319464411).

Almost surely, 2^2638928821 is an apocalyptic number.

It is an amenable number.

2638928821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2638928821 is an equidigital number, since it uses as much as digits as its factorization.

2638928821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 663552, while the sum is 49.

The square root of 2638928821 is about 51370.5053605666. The cubic root of 2638928821 is about 1381.8976939408.

The spelling of 2638928821 in words is "two billion, six hundred thirty-eight million, nine hundred twenty-eight thousand, eight hundred twenty-one".