121800421 has 4 divisors (see below), whose sum is σ = 122006412. Its totient is φ = 121594432.

The previous prime is 121800409. The next prime is 121800451. The reversal of 121800421 is 124008121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 37344321 + 84456100 = 6111^2 + 9190^2 .

It is a cyclic number.

It is not a de Polignac number, because 121800421 - 2⁵ = 121800389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121800451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 102106 + ... + 103291.

It is an arithmetic number, because the mean of its divisors is an integer number (30501603).

Almost surely, 2^121800421 is an apocalyptic number.

It is an amenable number.

121800421 is a deficient number, since it is larger than the sum of its proper divisors (205991).

121800421 is an equidigital number, since it uses as much as digits as its factorization.

121800421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205990.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 121800421 is about 11036.3228024555. The cubic root of 121800421 is about 495.6969687444.

Adding to 121800421 its reverse (124008121), we get a palindrome (245808542).

It can be divided in two parts, 121800 and 421, that added together give a palindrome (122221).

The spelling of 121800421 in words is "one hundred twenty-one million, eight hundred thousand, four hundred twenty-one".