6721778451 has 16 divisors (see below), whose sum is σ = 9362110464. Its totient is φ = 4281735744.

The previous prime is 6721778449. The next prime is 6721778501. The reversal of 6721778451 is 1548771276.

It is not a de Polignac number, because 6721778451 - 2¹ = 6721778449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6721778451.

It is not an unprimeable number, because it can be changed into a prime (6721778051) 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, 12670 + ... + 116636.

It is an arithmetic number, because the mean of its divisors is an integer number (585131904).

Almost surely, 2^6721778451 is an apocalyptic number.

6721778451 is a deficient number, since it is larger than the sum of its proper divisors (2640332013).

6721778451 is a wasteful number, since it uses less digits than its factorization.

6721778451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104930.

The product of its digits is 658560, while the sum is 48.

The square root of 6721778451 is about 81986.4528504557. The cubic root of 6721778451 is about 1887.2440494189.

The spelling of 6721778451 in words is "six billion, seven hundred twenty-one million, seven hundred seventy-eight thousand, four hundred fifty-one".