6918721845 has 48 divisors (see below), whose sum is σ = 13555074240. Its totient is φ = 2996372736.

The previous prime is 6918721837. The next prime is 6918721891. The reversal of 6918721845 is 5481278196.

It is not a de Polignac number, because 6918721845 - 2³ = 6918721837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 233752 + ... + 261681.

It is an arithmetic number, because the mean of its divisors is an integer number (282397380).

Almost surely, 2^6918721845 is an apocalyptic number.

It is an amenable number.

6918721845 is a deficient number, since it is larger than the sum of its proper divisors (6636352395).

6918721845 is a wasteful number, since it uses less digits than its factorization.

6918721845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495474 (or 495467 counting only the distinct ones).

The product of its digits is 967680, while the sum is 51.

The square root of 6918721845 is about 83178.8545545080. The cubic root of 6918721845 is about 1905.4985544212.

The spelling of 6918721845 in words is "six billion, nine hundred eighteen million, seven hundred twenty-one thousand, eight hundred forty-five".