261664516648 has 32 divisors (see below), whose sum is σ = 491835672000. Its totient is φ = 130508485632.

The previous prime is 261664516637. The next prime is 261664516651. The reversal of 261664516648 is 846615466162.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21786661 + ... + 21798667.

It is an arithmetic number, because the mean of its divisors is an integer number (15369864750).

Almost surely, 2^261664516648 is an apocalyptic number.

It is an amenable number.

261664516648 is a deficient number, since it is larger than the sum of its proper divisors (230171155352).

261664516648 is a wasteful number, since it uses less digits than its factorization.

261664516648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18529 (or 18525 counting only the distinct ones).

The product of its digits is 9953280, while the sum is 55.

The spelling of 261664516648 in words is "two hundred sixty-one billion, six hundred sixty-four million, five hundred sixteen thousand, six hundred forty-eight".