18959999 has 6 divisors (see below), whose sum is σ = 19435440. Its totient is φ = 18495920.

The previous prime is 18959987. The next prime is 18960031. The reversal of 18959999 is 99995981.

It is a de Polignac number, because none of the positive numbers 2^k-18959999 is a prime.

It is a Duffinian number.

18959999 is a modest number, since divided by 9999 gives 1895 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18959099) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3959 + ... + 7320.

It is an arithmetic number, because the mean of its divisors is an integer number (3239240).

Almost surely, 2^18959999 is an apocalyptic number.

18959999 is a deficient number, since it is larger than the sum of its proper divisors (475441).

18959999 is an equidigital number, since it uses as much as digits as its factorization.

18959999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11361 (or 11320 counting only the distinct ones).

The product of its digits is 2361960, while the sum is 59.

The square root of 18959999 is about 4354.3080965866. The cubic root of 18959999 is about 266.6527723663.

The spelling of 18959999 in words is "eighteen million, nine hundred fifty-nine thousand, nine hundred ninety-nine".