18009261 has 12 divisors (see below), whose sum is σ = 26910780. Its totient is φ = 11592000.

The previous prime is 18009259. The next prime is 18009287. The reversal of 18009261 is 16290081.

It can be written as a sum of positive squares in 2 ways, for example, as 3493161 + 14516100 = 1869^2 + 3810^2 .

It is not a de Polignac number, because 18009261 - 2¹ = 18009259 is a prime.

It is a super-2 number, since 2×18009261² = 648666963532242, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18009461) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34240 + ... + 34761.

It is an arithmetic number, because the mean of its divisors is an integer number (2242565).

Almost surely, 2^18009261 is an apocalyptic number.

It is an amenable number.

18009261 is a deficient number, since it is larger than the sum of its proper divisors (8901519).

18009261 is a wasteful number, since it uses less digits than its factorization.

18009261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69036 (or 69033 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 18009261 is about 4243.7319660883. The cubic root of 18009261 is about 262.1190774298.

The spelling of 18009261 in words is "eighteen million, nine thousand, two hundred sixty-one".