6405749821 has 8 divisors (see below), whose sum is σ = 7001351424. Its totient is φ = 5834458560.

The previous prime is 6405749807. The next prime is 6405749827. The reversal of 6405749821 is 1289475046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6405749821 - 2¹¹ = 6405747773 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 (6405749827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6077035 + ... + 6078088.

It is an arithmetic number, because the mean of its divisors is an integer number (875168928).

Almost surely, 2^6405749821 is an apocalyptic number.

It is an amenable number.

6405749821 is a deficient number, since it is larger than the sum of its proper divisors (595601603).

6405749821 is a wasteful number, since it uses less digits than its factorization.

6405749821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12155171.

The product of its (nonzero) digits is 483840, while the sum is 46.

The square root of 6405749821 is about 80035.9283134768. The cubic root of 6405749821 is about 1857.1913733741.

The spelling of 6405749821 in words is "six billion, four hundred five million, seven hundred forty-nine thousand, eight hundred twenty-one".