121005561320 has 128 divisors (see below), whose sum is σ = 312874824960. Its totient is φ = 41259171840.

The previous prime is 121005561311. The next prime is 121005561343. The reversal of 121005561320 is 23165500121.

It is a self number, because there is not a number n which added to its sum of digits gives 121005561320.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67713467 + ... + 67715253.

It is an arithmetic number, because the mean of its divisors is an integer number (2444334570).

Almost surely, 2^121005561320 is an apocalyptic number.

121005561320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121005561320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (156437412480).

121005561320 is an abundant number, since it is smaller than the sum of its proper divisors (191869263640).

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

121005561320 is a wasteful number, since it uses less digits than its factorization.

121005561320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003 (or 2999 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 26.

The spelling of 121005561320 in words is "one hundred twenty-one billion, five million, five hundred sixty-one thousand, three hundred twenty".