121561945680 has 320 divisors, whose sum is σ = 438057676800. Its totient is φ = 27311800320.

The previous prime is 121561945663. The next prime is 121561945691. The reversal of 121561945680 is 86549165121.

121561945680 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 45205776 + ... + 45208464.

It is an arithmetic number, because the mean of its divisors is an integer number (1368930240).

Almost surely, 2^121561945680 is an apocalyptic number.

121561945680 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 121561945680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (219028838400).

121561945680 is an abundant number, since it is smaller than the sum of its proper divisors (316495731120).

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

121561945680 is a wasteful number, since it uses less digits than its factorization.

121561945680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3162 (or 3156 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 48.

The spelling of 121561945680 in words is "one hundred twenty-one billion, five hundred sixty-one million, nine hundred forty-five thousand, six hundred eighty".