18891540 has 36 divisors (see below), whose sum is σ = 57304884. Its totient is φ = 5037696.

The previous prime is 18891527. The next prime is 18891559. The reversal of 18891540 is 4519881.

It can be written as a sum of positive squares in 2 ways, for example, as 5363856 + 13527684 = 2316^2 + 3678^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18891495 and 18891504.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52297 + ... + 52656.

Almost surely, 2^18891540 is an apocalyptic number.

18891540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18891540 is an abundant number, since it is smaller than the sum of its proper divisors (38413344).

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

18891540 is a wasteful number, since it uses less digits than its factorization.

18891540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104968 (or 104963 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 18891540 is about 4346.4399225113. The cubic root of 18891540 is about 266.3314503168.

The spelling of 18891540 in words is "eighteen million, eight hundred ninety-one thousand, five hundred forty".