121521533520 has 80 divisors (see below), whose sum is σ = 376889395392. Its totient is φ = 32390891520.

The previous prime is 121521533509. The next prime is 121521533533. The reversal of 121521533520 is 25335125121.

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

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 413800 + ... + 643640.

Almost surely, 2^121521533520 is an apocalyptic number.

121521533520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121521533520 is an abundant number, since it is smaller than the sum of its proper divisors (255367861872).

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

121521533520 is a wasteful number, since it uses less digits than its factorization.

121521533520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232060 (or 232054 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

Adding to 121521533520 its reverse (25335125121), we get a palindrome (146856658641).

The spelling of 121521533520 in words is "one hundred twenty-one billion, five hundred twenty-one million, five hundred thirty-three thousand, five hundred twenty".