6420639916 has 6 divisors (see below), whose sum is σ = 11236119860. Its totient is φ = 3210319956.

The previous prime is 6420639913. The next prime is 6420639931. The reversal of 6420639916 is 6199360246.

It is not an unprimeable number, because it can be changed into a prime (6420639913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802579986 + ... + 802579993.

Almost surely, 2^6420639916 is an apocalyptic number.

It is an amenable number.

6420639916 is a deficient number, since it is larger than the sum of its proper divisors (4815479944).

6420639916 is a wasteful number, since it uses less digits than its factorization.

6420639916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1605159983 (or 1605159981 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 46.

The square root of 6420639916 is about 80128.8956369673. The cubic root of 6420639916 is about 1858.6292667997.

The spelling of 6420639916 in words is "six billion, four hundred twenty million, six hundred thirty-nine thousand, nine hundred sixteen".