18012421 has 16 divisors (see below), whose sum is σ = 21441024. Its totient is φ = 14811264.

The previous prime is 18012419. The next prime is 18012431. The reversal of 18012421 is 12421081.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18012421 - 2¹ = 18012419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18012431) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16921 + ... + 17953.

It is an arithmetic number, because the mean of its divisors is an integer number (1340064).

Almost surely, 2^18012421 is an apocalyptic number.

It is an amenable number.

18012421 is a deficient number, since it is larger than the sum of its proper divisors (3428603).

18012421 is a wasteful number, since it uses less digits than its factorization.

18012421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1140.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 18012421 is about 4244.1042635637. The cubic root of 18012421 is about 262.1344074655.

The spelling of 18012421 in words is "eighteen million, twelve thousand, four hundred twenty-one".