18815420 has 24 divisors (see below), whose sum is σ = 42552384. Its totient is φ = 6947136.

The previous prime is 18815417. The next prime is 18815437. The reversal of 18815420 is 2451881.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35924 + ... + 36443.

It is an arithmetic number, because the mean of its divisors is an integer number (1773016).

Almost surely, 2^18815420 is an apocalyptic number.

18815420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18815420 is an abundant number, since it is smaller than the sum of its proper divisors (23736964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18815420 is a wasteful number, since it uses less digits than its factorization.

18815420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72389 (or 72387 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 29.

The square root of 18815420 is about 4337.6744921674. The cubic root of 18815420 is about 265.9732575297.

It can be divided in two parts, 18815 and 420, that multiplied together give a triangular number (7902300 = T₃₉₇₅).

The spelling of 18815420 in words is "eighteen million, eight hundred fifteen thousand, four hundred twenty".