121521400 has 192 divisors, whose sum is σ = 379975680. Its totient is φ = 34905600.

The previous prime is 121521377. The next prime is 121521427. The reversal of 121521400 is 4125121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 199897 + ... + 200503.

It is an arithmetic number, because the mean of its divisors is an integer number (1979040).

Almost surely, 2^121521400 is an apocalyptic number.

121521400 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 121521400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (189987840).

121521400 is an abundant number, since it is smaller than the sum of its proper divisors (258454280).

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

121521400 is a wasteful number, since it uses less digits than its factorization.

121521400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 645 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 121521400 is about 11023.6745234971. The cubic root of 121521400 is about 495.3181643280.

Adding to 121521400 its reverse (4125121), we get a palindrome (125646521).

The spelling of 121521400 in words is "one hundred twenty-one million, five hundred twenty-one thousand, four hundred".