121205406 has 32 divisors (see below), whose sum is σ = 278304768. Its totient is φ = 34472160.

The previous prime is 121205401. The next prime is 121205429. The reversal of 121205406 is 604502121.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121205401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2896 + ... + 15836.

It is an arithmetic number, because the mean of its divisors is an integer number (8697024).

Almost surely, 2^121205406 is an apocalyptic number.

121205406 is an abundant number, since it is smaller than the sum of its proper divisors (157099362).

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

121205406 is a wasteful number, since it uses less digits than its factorization.

121205406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13176.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 121205406 is about 11009.3326773243. The cubic root of 121205406 is about 494.8884637996. Note that the first 3 decimals are identical.

Adding to 121205406 its reverse (604502121), we get a palindrome (725707527).

The spelling of 121205406 in words is "one hundred twenty-one million, two hundred five thousand, four hundred six".