121551320 has 64 divisors (see below), whose sum is σ = 311351040. Its totient is φ = 42275200.

The previous prime is 121551317. The next prime is 121551329. The reversal of 121551320 is 23155121.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 121551292 and 121551301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121551329) 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, 4115 + ... + 16125.

It is an arithmetic number, because the mean of its divisors is an integer number (4864860).

Almost surely, 2^121551320 is an apocalyptic number.

121551320 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 121551320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155675520).

121551320 is an abundant number, since it is smaller than the sum of its proper divisors (189799720).

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

121551320 is a wasteful number, since it uses less digits than its factorization.

121551320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12056 (or 12052 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 20.

The square root of 121551320 is about 11025.0315192293. The cubic root of 121551320 is about 495.3588120476.

The spelling of 121551320 in words is "one hundred twenty-one million, five hundred fifty-one thousand, three hundred twenty".