6864651221 has 4 divisors (see below), whose sum is σ = 7268454252. Its totient is φ = 6460848192.

The previous prime is 6864651217. The next prime is 6864651251. The reversal of 6864651221 is 1221564686.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2254920196 + 4609731025 = 47486^2 + 67895^2 .

It is a cyclic number.

It is not a de Polignac number, because 6864651221 - 2² = 6864651217 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 (6864651251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 201901490 + ... + 201901523.

It is an arithmetic number, because the mean of its divisors is an integer number (1817113563).

Almost surely, 2^6864651221 is an apocalyptic number.

It is an amenable number.

6864651221 is a deficient number, since it is larger than the sum of its proper divisors (403803031).

6864651221 is a wasteful number, since it uses less digits than its factorization.

6864651221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 403803030.

The product of its digits is 138240, while the sum is 41.

The square root of 6864651221 is about 82853.1907713879. The cubic root of 6864651221 is about 1900.5216684830.

The spelling of 6864651221 in words is "six billion, eight hundred sixty-four million, six hundred fifty-one thousand, two hundred twenty-one".