18530521965 has 24 divisors (see below), whose sum is σ = 32132920248. Its totient is φ = 9878837760.

The previous prime is 18530521949. The next prime is 18530521967. The reversal of 18530521965 is 56912503581.

18530521965 is a `hidden beast` number, since 1 + 8 + 5 + 30 + 521 + 96 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 814645764 + 17715876201 = 28542^2 + 133101^2 .

It is not a de Polignac number, because 18530521965 - 2⁴ = 18530521949 is a prime.

It is a super-2 number, since 2×18530521965² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 18530521965.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18530521967) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25497 + ... + 194193.

It is an arithmetic number, because the mean of its divisors is an integer number (1338871677).

Almost surely, 2^18530521965 is an apocalyptic number.

18530521965 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18530521965 is a deficient number, since it is larger than the sum of its proper divisors (13602398283).

18530521965 is a wasteful number, since it uses less digits than its factorization.

18530521965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171149 (or 171146 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 45.

The spelling of 18530521965 in words is "eighteen billion, five hundred thirty million, five hundred twenty-one thousand, nine hundred sixty-five".