6403642661 has 8 divisors (see below), whose sum is σ = 6899020800. Its totient is φ = 5908663152.

The previous prime is 6403642657. The next prime is 6403642667. The reversal of 6403642661 is 1662463046.

It is a happy number.

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 6403642661 - 2² = 6403642657 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 (6403642667) 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, 65861 + ... + 130938.

It is an arithmetic number, because the mean of its divisors is an integer number (862377600).

Almost surely, 2^6403642661 is an apocalyptic number.

It is an amenable number.

6403642661 is a deficient number, since it is larger than the sum of its proper divisors (495378139).

6403642661 is a wasteful number, since it uses less digits than its factorization.

6403642661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199315.

The product of its (nonzero) digits is 124416, while the sum is 38.

The square root of 6403642661 is about 80022.7633926747. The cubic root of 6403642661 is about 1856.9877111090.

The spelling of 6403642661 in words is "six billion, four hundred three million, six hundred forty-two thousand, six hundred sixty-one".