7881764821 has 16 divisors (see below), whose sum is σ = 9485625600. Its totient is φ = 6402768768.

The previous prime is 7881764819. The next prime is 7881764857. The reversal of 7881764821 is 1284671887.

7881764821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 7881764821 - 2¹ = 7881764819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7881764881) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207016 + ... + 242113.

It is an arithmetic number, because the mean of its divisors is an integer number (592851600).

Almost surely, 2^7881764821 is an apocalyptic number.

It is an amenable number.

7881764821 is a deficient number, since it is larger than the sum of its proper divisors (1603860779).

7881764821 is a wasteful number, since it uses less digits than its factorization.

7881764821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449268.

The product of its digits is 1204224, while the sum is 52.

The square root of 7881764821 is about 88779.3040128160. The cubic root of 7881764821 is about 1990.0981257642.

The spelling of 7881764821 in words is "seven billion, eight hundred eighty-one million, seven hundred sixty-four thousand, eight hundred twenty-one".