12121905 has 16 divisors (see below), whose sum is σ = 20416320. Its totient is φ = 6124608.

The previous prime is 12121883. The next prime is 12121927. The reversal of 12121905 is 50912121.

It is an interprime number because it is at equal distance from previous prime (12121883) and next prime (12121927).

It is not a de Polignac number, because 12121905 - 2⁵ = 12121873 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20982 + ... + 21551.

It is an arithmetic number, because the mean of its divisors is an integer number (1276020).

Almost surely, 2^12121905 is an apocalyptic number.

12121905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12121905 is a deficient number, since it is larger than the sum of its proper divisors (8294415).

12121905 is a wasteful number, since it uses less digits than its factorization.

12121905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42560.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 12121905 is about 3481.6526248321. The cubic root of 12121905 is about 229.7154957314.

The spelling of 12121905 in words is "twelve million, one hundred twenty-one thousand, nine hundred five".