12147921 has 16 divisors (see below), whose sum is σ = 18083520. Its totient is φ = 8059680.

The previous prime is 12147917. The next prime is 12147943. The reversal of 12147921 is 12974121.

It is not a de Polignac number, because 12147921 - 2² = 12147917 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12147221) 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 15 ways as a sum of consecutive naturals, for example, 5326 + ... + 7256.

It is an arithmetic number, because the mean of its divisors is an integer number (1130220).

Almost surely, 2^12147921 is an apocalyptic number.

It is an amenable number.

12147921 is a deficient number, since it is larger than the sum of its proper divisors (5935599).

12147921 is a wasteful number, since it uses less digits than its factorization.

12147921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2173 (or 2167 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 12147921 is about 3485.3867791107. The cubic root of 12147921 is about 229.8797165643.

The spelling of 12147921 in words is "twelve million, one hundred forty-seven thousand, nine hundred twenty-one".