121220400 has 120 divisors (see below), whose sum is σ = 443812864. Its totient is φ = 27705600.

The previous prime is 121220389. The next prime is 121220401. The reversal of 121220400 is 4022121.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (121220401) 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, 1185 + ... + 15615.

Almost surely, 2^121220400 is an apocalyptic number.

121220400 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 121220400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221906432).

121220400 is an abundant number, since it is smaller than the sum of its proper divisors (322592464).

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

121220400 is a wasteful number, since it uses less digits than its factorization.

121220400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14459 (or 14448 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 121220400 is about 11010.0136239698. The cubic root of 121220400 is about 494.9088700722.

Adding to 121220400 its reverse (4022121), we get a palindrome (125242521).

It can be divided in two parts, 1212 and 20400, that added together give a palindrome (21612).

The spelling of 121220400 in words is "one hundred twenty-one million, two hundred twenty thousand, four hundred".