6421634663 has 4 divisors (see below), whose sum is σ = 6570975048. Its totient is φ = 6272294280.

The previous prime is 6421634657. The next prime is 6421634671. The reversal of 6421634663 is 3664361246.

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

It is a cyclic number.

It is not a de Polignac number, because 6421634663 - 2¹⁰ = 6421633639 is a prime.

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 6421634663.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6421634603) 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, 74670128 + ... + 74670213.

It is an arithmetic number, because the mean of its divisors is an integer number (1642743762).

Almost surely, 2^6421634663 is an apocalyptic number.

6421634663 is a deficient number, since it is larger than the sum of its proper divisors (149340385).

6421634663 is a wasteful number, since it uses less digits than its factorization.

6421634663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149340384.

The product of its digits is 373248, while the sum is 41.

The square root of 6421634663 is about 80135.1025643569. The cubic root of 6421634663 is about 1858.7252473893.

The spelling of 6421634663 in words is "six billion, four hundred twenty-one million, six hundred thirty-four thousand, six hundred sixty-three".