121605644553 has 24 divisors (see below), whose sum is σ = 173554566240. Its totient is φ = 75719055360.

The previous prime is 121605644527. The next prime is 121605644579. The reversal of 121605644553 is 355446506121.

It is an interprime number because it is at equal distance from previous prime (121605644527) and next prime (121605644579).

It is not a de Polignac number, because 121605644553 - 2⁸ = 121605644297 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121605644593) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 421768 + ... + 648921.

It is an arithmetic number, because the mean of its divisors is an integer number (7231440260).

Almost surely, 2^121605644553 is an apocalyptic number.

It is an amenable number.

121605644553 is a deficient number, since it is larger than the sum of its proper divisors (51948921687).

121605644553 is a wasteful number, since it uses less digits than its factorization.

121605644553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1070857 (or 1070840 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 42.

The spelling of 121605644553 in words is "one hundred twenty-one billion, six hundred five million, six hundred forty-four thousand, five hundred fifty-three".