6421964647 has 12 divisors (see below), whose sum is σ = 7490902800. Its totient is φ = 5503268988.

The previous prime is 6421964639. The next prime is 6421964699. The reversal of 6421964647 is 7464691246.

It is a happy number.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is not a de Polignac number, because 6421964647 - 2³ = 6421964639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6421964647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6421964447) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1481998 + ... + 1486324.

It is an arithmetic number, because the mean of its divisors is an integer number (624241900).

Almost surely, 2^6421964647 is an apocalyptic number.

6421964647 is a deficient number, since it is larger than the sum of its proper divisors (1068938153).

6421964647 is an frugal number, since it uses more digits than its factorization.

6421964647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8675 (or 4334 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 49.

The square root of 6421964647 is about 80137.1614608354. The cubic root of 6421964647 is about 1858.7570845106.

The spelling of 6421964647 in words is "six billion, four hundred twenty-one million, nine hundred sixty-four thousand, six hundred forty-seven".