120721556165 has 16 divisors (see below), whose sum is σ = 165593579520. Its totient is φ = 82764201600.

The previous prime is 120721556141. The next prime is 120721556173. The reversal of 120721556165 is 561655127021.

It is not a de Polignac number, because 120721556165 - 2¹² = 120721552069 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 157736 + ... + 516065.

It is an arithmetic number, because the mean of its divisors is an integer number (10349598720).

Almost surely, 2^120721556165 is an apocalyptic number.

It is an amenable number.

120721556165 is a deficient number, since it is larger than the sum of its proper divisors (44872023355).

120721556165 is an equidigital number, since it uses as much as digits as its factorization.

120721556165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678932.

The product of its (nonzero) digits is 126000, while the sum is 41.

The spelling of 120721556165 in words is "one hundred twenty billion, seven hundred twenty-one million, five hundred fifty-six thousand, one hundred sixty-five".