6642640401 has 16 divisors (see below), whose sum is σ = 9483220800. Its totient is φ = 4121097728.

The previous prime is 6642640393. The next prime is 6642640421. The reversal of 6642640401 is 1040462466.

It is a cyclic number.

It is not a de Polignac number, because 6642640401 - 2³ = 6642640393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6642640421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 727191 + ... + 736268.

It is an arithmetic number, because the mean of its divisors is an integer number (592701300).

Almost surely, 2^6642640401 is an apocalyptic number.

It is an amenable number.

6642640401 is a deficient number, since it is larger than the sum of its proper divisors (2840580399).

6642640401 is a wasteful number, since it uses less digits than its factorization.

6642640401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1463568.

The product of its (nonzero) digits is 27648, while the sum is 33.

The square root of 6642640401 is about 81502.3950629673. The cubic root of 6642640401 is about 1879.8083780285.

The spelling of 6642640401 in words is "six billion, six hundred forty-two million, six hundred forty thousand, four hundred one".