12151921 has 4 divisors (see below), whose sum is σ = 12160000. Its totient is φ = 12143844.

The previous prime is 12151901. The next prime is 12151927. The reversal of 12151921 is 12915121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 12151921 - 2⁹ = 12151409 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12151892 and 12151901.

It is not an unprimeable number, because it can be changed into a prime (12151927) 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, 1041 + ... + 5038.

It is an arithmetic number, because the mean of its divisors is an integer number (3040000).

Almost surely, 2^12151921 is an apocalyptic number.

It is an amenable number.

12151921 is a deficient number, since it is larger than the sum of its proper divisors (8079).

12151921 is an equidigital number, since it uses as much as digits as its factorization.

12151921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8078.

The product of its digits is 180, while the sum is 22.

The square root of 12151921 is about 3485.9605562886. The cubic root of 12151921 is about 229.9049449678.

It can be divided in two parts, 1215 and 1921, that added together give a square (3136 = 56²).

The spelling of 12151921 in words is "twelve million, one hundred fifty-one thousand, nine hundred twenty-one".