18129890 has 8 divisors (see below), whose sum is σ = 32633820. Its totient is φ = 7251952.

The previous prime is 18129883. The next prime is 18129893. The reversal of 18129890 is 9892181.

It can be written as a sum of positive squares in 2 ways, for example, as 17547721 + 582169 = 4189^2 + 763^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×18129890² = 657385822824200, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18129893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 906485 + ... + 906504.

Almost surely, 2^18129890 is an apocalyptic number.

18129890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18129890 is a deficient number, since it is larger than the sum of its proper divisors (14503930).

18129890 is a wasteful number, since it uses less digits than its factorization.

18129890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812996.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 18129890 is about 4257.9208541259. The cubic root of 18129890 is about 262.7030145301.

The spelling of 18129890 in words is "eighteen million, one hundred twenty-nine thousand, eight hundred ninety".