18060721 has 16 divisors (see below), whose sum is σ = 21218176. Its totient is φ = 15054336.

The previous prime is 18060701. The next prime is 18060733. The reversal of 18060721 is 12706081.

18060721 = T₁₃₀₁ + T₁₃₀₂ + ... + T₁₃₂₁.

It is a cyclic number.

It is not a de Polignac number, because 18060721 - 2⁷ = 18060593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18060701) 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, 45295 + ... + 45691.

It is an arithmetic number, because the mean of its divisors is an integer number (1326136).

Almost surely, 2^18060721 is an apocalyptic number.

It is an amenable number.

18060721 is a deficient number, since it is larger than the sum of its proper divisors (3157455).

18060721 is an equidigital number, since it uses as much as digits as its factorization.

18060721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 18060721 is about 4249.7907007287. The cubic root of 18060721 is about 262.3685013329.

It can be divided in two parts, 18060 and 721, that added together give a palindrome (18781).

The spelling of 18060721 in words is "eighteen million, sixty thousand, seven hundred twenty-one".