12155421 has 8 divisors (see below), whose sum is σ = 17060320. Its totient is φ = 7677072.

The previous prime is 12155419. The next prime is 12155447. The reversal of 12155421 is 12455121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12155421 - 2¹ = 12155419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12155401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106570 + ... + 106683.

It is an arithmetic number, because the mean of its divisors is an integer number (2132540).

Almost surely, 2^12155421 is an apocalyptic number.

It is an amenable number.

12155421 is a deficient number, since it is larger than the sum of its proper divisors (4904899).

12155421 is a wasteful number, since it uses less digits than its factorization.

12155421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213275.

The product of its digits is 400, while the sum is 21.

The square root of 12155421 is about 3486.4625338586. The cubic root of 12155421 is about 229.9270152799.

The spelling of 12155421 in words is "twelve million, one hundred fifty-five thousand, four hundred twenty-one".