518172981 has 8 divisors (see below), whose sum is σ = 700628544. Its totient is φ = 340583040.

The previous prime is 518172973. The next prime is 518173001. The reversal of 518172981 is 189271815.

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

It is not a de Polignac number, because 518172981 - 2³ = 518172973 is a prime.

It is a super-2 number, since 2×518172981² = 537006476476852722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (518172931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1216156 + ... + 1216581.

It is an arithmetic number, because the mean of its divisors is an integer number (87578568).

Almost surely, 2^518172981 is an apocalyptic number.

It is an amenable number.

518172981 is a deficient number, since it is larger than the sum of its proper divisors (182455563).

518172981 is a wasteful number, since it uses less digits than its factorization.

518172981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2432811.

The product of its digits is 40320, while the sum is 42.

The square root of 518172981 is about 22763.4132106765. The cubic root of 518172981 is about 803.2022590889.

The spelling of 518172981 in words is "five hundred eighteen million, one hundred seventy-two thousand, nine hundred eighty-one".