18955431 has 16 divisors (see below), whose sum is σ = 30635520. Its totient is φ = 11487960.

The previous prime is 18955403. The next prime is 18955451. The reversal of 18955431 is 13455981.

It is not a de Polignac number, because 18955431 - 2¹⁰ = 18954407 is a prime.

It is a super-2 number, since 2×18955431² = 718616728791522, which contains 22 as substring.

It is a nialpdrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18955451) 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, 31615 + ... + 32208.

It is an arithmetic number, because the mean of its divisors is an integer number (1914720).

Almost surely, 2^18955431 is an apocalyptic number.

18955431 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18955431 is a deficient number, since it is larger than the sum of its proper divisors (11680089).

18955431 is a wasteful number, since it uses less digits than its factorization.

18955431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63843 (or 63837 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 18955431 is about 4353.7835270027. The cubic root of 18955431 is about 266.6313559148.

The spelling of 18955431 in words is "eighteen million, nine hundred fifty-five thousand, four hundred thirty-one".