121565721006 has 48 divisors (see below), whose sum is σ = 272519395200. Its totient is φ = 39118209984.

The previous prime is 121565720987. The next prime is 121565721007. The reversal of 121565721006 is 600127565121.

121565721006 is a `hidden beast` number, since 1 + 21 + 56 + 572 + 10 + 0 + 6 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121565721007) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3988035 + ... + 4018401.

It is an arithmetic number, because the mean of its divisors is an integer number (5677487400).

Almost surely, 2^121565721006 is an apocalyptic number.

121565721006 is an abundant number, since it is smaller than the sum of its proper divisors (150953674194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121565721006 is a wasteful number, since it uses less digits than its factorization.

121565721006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38073 (or 38070 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 121565721006 in words is "one hundred twenty-one billion, five hundred sixty-five million, seven hundred twenty-one thousand, six".