6665400650 has 12 divisors (see below), whose sum is σ = 12397645302. Its totient is φ = 2666160240.

The previous prime is 6665400649. The next prime is 6665400671. The reversal of 6665400650 is 560045666.

It can be written as a sum of positive squares in 3 ways, for example, as 5717930689 + 947469961 = 75617^2 + 30781^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 66653957 + ... + 66654056.

Almost surely, 2^6665400650 is an apocalyptic number.

6665400650 is a deficient number, since it is larger than the sum of its proper divisors (5732244652).

6665400650 is a wasteful number, since it uses less digits than its factorization.

6665400650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133308025 (or 133308020 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 38.

The square root of 6665400650 is about 81641.9049875736. The cubic root of 6665400650 is about 1881.9529134902.

The spelling of 6665400650 in words is "six billion, six hundred sixty-five million, four hundred thousand, six hundred fifty".