6420777906 has 64 divisors (see below), whose sum is σ = 13995427968. Its totient is φ = 1955570688.

The previous prime is 6420777887. The next prime is 6420777907. The reversal of 6420777906 is 6097770246.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (6420777907) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1972176 + ... + 1975428.

It is an arithmetic number, because the mean of its divisors is an integer number (218678562).

Almost surely, 2^6420777906 is an apocalyptic number.

6420777906 is an abundant number, since it is smaller than the sum of its proper divisors (7574650062).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6420777906 is a wasteful number, since it uses less digits than its factorization.

6420777906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3835.

The product of its (nonzero) digits is 889056, while the sum is 48.

The square root of 6420777906 is about 80129.7566825209. The cubic root of 6420777906 is about 1858.6425816934.

The spelling of 6420777906 in words is "six billion, four hundred twenty million, seven hundred seventy-seven thousand, nine hundred six".