1818616521 has 16 divisors (see below), whose sum is σ = 2554807040. Its totient is φ = 1147536720.

The previous prime is 1818616487. The next prime is 1818616529. The reversal of 1818616521 is 1256168181.

It is not a de Polignac number, because 1818616521 - 2²² = 1814422217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1818616521.

It is not an unprimeable number, because it can be changed into a prime (1818616529) 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, 49806 + ... + 78216.

It is an arithmetic number, because the mean of its divisors is an integer number (159675440).

Almost surely, 2^1818616521 is an apocalyptic number.

It is an amenable number.

1818616521 is a deficient number, since it is larger than the sum of its proper divisors (736190519).

1818616521 is a wasteful number, since it uses less digits than its factorization.

1818616521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29556.

The product of its digits is 23040, while the sum is 39.

The square root of 1818616521 is about 42645.2403088551. The cubic root of 1818616521 is about 1220.6197068861.

The spelling of 1818616521 in words is "one billion, eight hundred eighteen million, six hundred sixteen thousand, five hundred twenty-one".