18851421 has 16 divisors (see below), whose sum is σ = 27135360. Its totient is φ = 11605440.

The previous prime is 18851407. The next prime is 18851473. The reversal of 18851421 is 12415881.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-18851421 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18851221) 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, 2710 + ... + 6711.

It is an arithmetic number, because the mean of its divisors is an integer number (1695960).

Almost surely, 2^18851421 is an apocalyptic number.

It is an amenable number.

18851421 is a deficient number, since it is larger than the sum of its proper divisors (8283939).

18851421 is a wasteful number, since it uses less digits than its factorization.

18851421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9476.

The product of its digits is 2560, while the sum is 30.

The square root of 18851421 is about 4341.8223132689. The cubic root of 18851421 is about 266.1427851950.

The spelling of 18851421 in words is "eighteen million, eight hundred fifty-one thousand, four hundred twenty-one".