121565721064 has 16 divisors (see below), whose sum is σ = 235795580100. Its totient is φ = 58686899712.

The previous prime is 121565721061. The next prime is 121565721083. The reversal of 121565721064 is 460127565121.

It can be written as a sum of positive squares in 2 ways, for example, as 116547132100 + 5018588964 = 341390^2 + 70842^2 .

It is not an unprimeable number, because it can be changed into a prime (121565721061) 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 3 ways as a sum of consecutive naturals, for example, 261994857 + ... + 261995320.

Almost surely, 2^121565721064 is an apocalyptic number.

It is an amenable number.

121565721064 is a deficient number, since it is larger than the sum of its proper divisors (114229859036).

121565721064 is a wasteful number, since it uses less digits than its factorization.

121565721064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523990212 (or 523990208 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 40.

The spelling of 121565721064 in words is "one hundred twenty-one billion, five hundred sixty-five million, seven hundred twenty-one thousand, sixty-four".