18358421 has 8 divisors (see below), whose sum is σ = 19060920. Its totient is φ = 17660608.

The previous prime is 18358387. The next prime is 18358423. The reversal of 18358421 is 12485381.

It can be written as a sum of positive squares in 4 ways, for example, as 600625 + 17757796 = 775^2 + 4214^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18358421 - 2¹⁸ = 18096277 is a prime.

It is a super-2 number, since 2×18358421² = 674063243226482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18358423) 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, 8195 + ... + 10191.

It is an arithmetic number, because the mean of its divisors is an integer number (2382615).

Almost surely, 2^18358421 is an apocalyptic number.

It is an amenable number.

18358421 is a deficient number, since it is larger than the sum of its proper divisors (702499).

18358421 is a wasteful number, since it uses less digits than its factorization.

18358421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2343.

The product of its digits is 7680, while the sum is 32.

The square root of 18358421 is about 4284.6727996429. The cubic root of 18358421 is about 263.8022173741.

The spelling of 18358421 in words is "eighteen million, three hundred fifty-eight thousand, four hundred twenty-one".