661640921324 has 24 divisors (see below), whose sum is σ = 1162397913600. Its totient is φ = 329527500624.

The previous prime is 661640921321. The next prime is 661640921351. The reversal of 661640921324 is 423129046166.

It is not an unprimeable number, because it can be changed into a prime (661640921321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11858717 + ... + 11914379.

It is an arithmetic number, because the mean of its divisors is an integer number (48433246400).

Almost surely, 2^661640921324 is an apocalyptic number.

It is an amenable number.

661640921324 is a deficient number, since it is larger than the sum of its proper divisors (500756992276).

661640921324 is a wasteful number, since it uses less digits than its factorization.

661640921324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67229 (or 67227 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 44.

The spelling of 661640921324 in words is "six hundred sixty-one billion, six hundred forty million, nine hundred twenty-one thousand, three hundred twenty-four".