121543400 has 96 divisors (see below), whose sum is σ = 311899680. Its totient is φ = 43680000.

The previous prime is 121543397. The next prime is 121543403. The reversal of 121543400 is 4345121.

It is an interprime number because it is at equal distance from previous prime (121543397) and next prime (121543403).

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

It is not an unprimeable number, because it can be changed into a prime (121543403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 221927 + ... + 222473.

It is an arithmetic number, because the mean of its divisors is an integer number (3248955).

Almost surely, 2^121543400 is an apocalyptic number.

121543400 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 121543400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155949840).

121543400 is an abundant number, since it is smaller than the sum of its proper divisors (190356280).

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

121543400 is a wasteful number, since it uses less digits than its factorization.

121543400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675 (or 666 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 121543400 is about 11024.6723307316. The cubic root of 121543400 is about 495.3480530063.

Adding to 121543400 its reverse (4345121), we get a palindrome (125888521).

The spelling of 121543400 in words is "one hundred twenty-one million, five hundred forty-three thousand, four hundred".