121005540 has 72 divisors (see below), whose sum is σ = 376991160. Its totient is φ = 31394304.

The previous prime is 121005539. The next prime is 121005581. The reversal of 121005540 is 45500121.

121005540 is a `hidden beast` number, since 12 + 100 + 554 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 14379264 + 106626276 = 3792^2 + 10326^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2425 + ... + 15744.

Almost surely, 2^121005540 is an apocalyptic number.

121005540 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 121005540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (188495580).

121005540 is an abundant number, since it is smaller than the sum of its proper divisors (255985620).

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

121005540 is a wasteful number, since it uses less digits than its factorization.

121005540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18221 (or 18216 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 121005540 is about 11000.2518152995. The cubic root of 121005540 is about 494.6162927839.

Adding to 121005540 its reverse (45500121), we get a palindrome (166505661).

The spelling of 121005540 in words is "one hundred twenty-one million, five thousand, five hundred forty".