6425406661 has 4 divisors (see below), whose sum is σ = 6704772192. Its totient is φ = 6146041132.

The previous prime is 6425406653. The next prime is 6425406671. The reversal of 6425406661 is 1666045246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6425406661 - 2³ = 6425406653 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 (6425406601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139682731 + ... + 139682776.

It is an arithmetic number, because the mean of its divisors is an integer number (1676193048).

Almost surely, 2^6425406661 is an apocalyptic number.

It is an amenable number.

6425406661 is a deficient number, since it is larger than the sum of its proper divisors (279365531).

6425406661 is a wasteful number, since it uses less digits than its factorization.

6425406661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279365530.

The product of its (nonzero) digits is 207360, while the sum is 40.

The square root of 6425406661 is about 80158.6343508920. The cubic root of 6425406661 is about 1859.0891077863.

The spelling of 6425406661 in words is "six billion, four hundred twenty-five million, four hundred six thousand, six hundred sixty-one".