121693840 has 40 divisors (see below), whose sum is σ = 284769720. Its totient is φ = 48362496.

The previous prime is 121693829. The next prime is 121693843. The reversal of 121693840 is 48396121.

It can be written as a sum of positive squares in 4 ways, for example, as 7118224 + 114575616 = 2668^2 + 10704^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 121693796 and 121693805.

It is not an unprimeable number, because it can be changed into a prime (121693843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7716 + ... + 17404.

It is an arithmetic number, because the mean of its divisors is an integer number (7119243).

Almost surely, 2^121693840 is an apocalyptic number.

121693840 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 121693840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142384860).

121693840 is an abundant number, since it is smaller than the sum of its proper divisors (163075880).

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

121693840 is a wasteful number, since it uses less digits than its factorization.

121693840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9859 (or 9853 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 121693840 is about 11031.4930993044. The cubic root of 121693840 is about 495.5523406284.

The spelling of 121693840 in words is "one hundred twenty-one million, six hundred ninety-three thousand, eight hundred forty".