121905800 has 48 divisors (see below), whose sum is σ = 288262800. Its totient is φ = 47931200.

The previous prime is 121905781. The next prime is 121905803. The reversal of 121905800 is 8509121.

It is a happy number.

It is a super-2 number, since 2×121905800² = 29722048147280000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 121905800.

It is not an unprimeable number, because it can be changed into a prime (121905803) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6635 + ... + 16965.

It is an arithmetic number, because the mean of its divisors is an integer number (6005475).

Almost surely, 2^121905800 is an apocalyptic number.

121905800 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 121905800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (144131400).

121905800 is an abundant number, since it is smaller than the sum of its proper divisors (166357000).

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

121905800 is a wasteful number, since it uses less digits than its factorization.

121905800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10406 (or 10397 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 121905800 is about 11041.0959600938. The cubic root of 121905800 is about 495.8398828471.

The spelling of 121905800 in words is "one hundred twenty-one million, nine hundred five thousand, eight hundred".