121561022780 has 96 divisors (see below), whose sum is σ = 272358180864. Its totient is φ = 45468301824.

The previous prime is 121561022777. The next prime is 121561022857. The reversal of 121561022780 is 87220165121.

It is a self number, because there is not a number n which added to its sum of digits gives 121561022780.

It is a congruent number.

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, 22330739 + ... + 22336181.

It is an arithmetic number, because the mean of its divisors is an integer number (2837064384).

Almost surely, 2^121561022780 is an apocalyptic number.

121561022780 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 121561022780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136179090432).

121561022780 is an abundant number, since it is smaller than the sum of its proper divisors (150797158084).

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

121561022780 is a wasteful number, since it uses less digits than its factorization.

121561022780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6555 (or 6553 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 35.

The spelling of 121561022780 in words is "one hundred twenty-one billion, five hundred sixty-one million, twenty-two thousand, seven hundred eighty".