121566001656 has 64 divisors (see below), whose sum is σ = 331848316800. Its totient is φ = 36804329600.

The previous prime is 121566001643. The next prime is 121566001657. The reversal of 121566001656 is 656100665121.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121566001657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76990 + ... + 499058.

It is an arithmetic number, because the mean of its divisors is an integer number (5185129950).

Almost surely, 2^121566001656 is an apocalyptic number.

It is an amenable number.

121566001656 is an abundant number, since it is smaller than the sum of its proper divisors (210282315144).

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

121566001656 is a wasteful number, since it uses less digits than its factorization.

121566001656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423180 (or 423176 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 39.

Adding to 121566001656 its reverse (656100665121), we get a palindrome (777666666777).

The spelling of 121566001656 in words is "one hundred twenty-one billion, five hundred sixty-six million, one thousand, six hundred fifty-six".