243640066761 has 48 divisors (see below), whose sum is σ = 458616622464. Its totient is φ = 120953820672.

The previous prime is 243640066757. The next prime is 243640066799. The reversal of 243640066761 is 167660046342.

It is a happy number.

It is not a de Polignac number, because 243640066761 - 2² = 243640066757 is a prime.

It is a super-2 number, since 2×243640066761² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (243640066711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8735631 + ... + 8763476.

It is an arithmetic number, because the mean of its divisors is an integer number (9554512968).

Almost surely, 2^243640066761 is an apocalyptic number.

243640066761 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

243640066761 is a deficient number, since it is larger than the sum of its proper divisors (214976555703).

243640066761 is a wasteful number, since it uses less digits than its factorization.

243640066761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17499150 (or 17499147 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 45.

The spelling of 243640066761 in words is "two hundred forty-three billion, six hundred forty million, sixty-six thousand, seven hundred sixty-one".