121212105 has 16 divisors (see below), whose sum is σ = 221645184. Its totient is φ = 55411200.

The previous prime is 121212103. The next prime is 121212127. The reversal of 121212105 is 501212121.

It is not a de Polignac number, because 121212105 - 2¹ = 121212103 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (121212103) 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, 577096 + ... + 577305.

It is an arithmetic number, because the mean of its divisors is an integer number (13852824).

Almost surely, 2^121212105 is an apocalyptic number.

121212105 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121212105 is a deficient number, since it is larger than the sum of its proper divisors (100433079).

121212105 is a wasteful number, since it uses less digits than its factorization.

121212105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154416.

The product of its (nonzero) digits is 40, while the sum is 15.

The square root of 121212105 is about 11009.6369149941. The cubic root of 121212105 is about 494.8975810958.

Adding to 121212105 its reverse (501212121), we get a palindrome (622424226).

It can be divided in two parts, 121 and 212105, that added together give a triangular number (212226 = T₆₅₁).

The spelling of 121212105 in words is "one hundred twenty-one million, two hundred twelve thousand, one hundred five".