121535440 has 80 divisors (see below), whose sum is σ = 306886608. Its totient is φ = 44494848.

The previous prime is 121535389. The next prime is 121535443. The reversal of 121535440 is 44535121.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 27290176 + 94245264 = 5224^2 + 9708^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121535443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142054 + ... + 142906.

Almost surely, 2^121535440 is an apocalyptic number.

121535440 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 121535440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (153443304).

121535440 is an abundant number, since it is smaller than the sum of its proper divisors (185351168).

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

121535440 is a wasteful number, since it uses less digits than its factorization.

121535440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016 (or 1010 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 121535440 is about 11024.3113163589. The cubic root of 121535440 is about 495.3372391555.

The spelling of 121535440 in words is "one hundred twenty-one million, five hundred thirty-five thousand, four hundred forty".