12121906 has 4 divisors (see below), whose sum is σ = 18182862. Its totient is φ = 6060952.

The previous prime is 12121883. The next prime is 12121927. The reversal of 12121906 is 60912121.

12121906 is nontrivially palindromic in base 5.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60912121 = 127 ⋅479623.

It can be written as a sum of positive squares in only one way, i.e., 10660225 + 1461681 = 3265^2 + 1209^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3030475 + ... + 3030478.

Almost surely, 2^12121906 is an apocalyptic number.

12121906 is a deficient number, since it is larger than the sum of its proper divisors (6060956).

12121906 is an equidigital number, since it uses as much as digits as its factorization.

12121906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6060955.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 12121906 is about 3481.6527684420. The cubic root of 12121906 is about 229.7155020483.

The spelling of 12121906 in words is "twelve million, one hundred twenty-one thousand, nine hundred six".