6420978777 has 8 divisors (see below), whose sum is σ = 8562628800. Its totient is φ = 4279990640.

The previous prime is 6420978763. The next prime is 6420978857. The reversal of 6420978777 is 7778790246.

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 6420978777 - 2¹⁰ = 6420977753 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6420978737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142374 + ... + 181967.

It is an arithmetic number, because the mean of its divisors is an integer number (1070328600).

Almost surely, 2^6420978777 is an apocalyptic number.

It is an amenable number.

6420978777 is a deficient number, since it is larger than the sum of its proper divisors (2141650023).

6420978777 is a wasteful number, since it uses less digits than its factorization.

6420978777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330943.

The product of its (nonzero) digits is 8297856, while the sum is 57.

The square root of 6420978777 is about 80131.0100834877. The cubic root of 6420978777 is about 1858.6619637427.

The spelling of 6420978777 in words is "six billion, four hundred twenty million, nine hundred seventy-eight thousand, seven hundred seventy-seven".