509649718 has 4 divisors (see below), whose sum is σ = 764474580. Its totient is φ = 254824858.

The previous prime is 509649713. The next prime is 509649743. The reversal of 509649718 is 817946905.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 817946905 = 5 ⋅163589381.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509649713) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 127412428 + ... + 127412431.

It is an arithmetic number, because the mean of its divisors is an integer number (191118645).

Almost surely, 2^509649718 is an apocalyptic number.

509649718 is a deficient number, since it is larger than the sum of its proper divisors (254824862).

509649718 is a wasteful number, since it uses less digits than its factorization.

509649718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254824861.

The product of its (nonzero) digits is 544320, while the sum is 49.

The square root of 509649718 is about 22575.4228753306. The cubic root of 509649718 is about 798.7740169584.

The spelling of 509649718 in words is "five hundred nine million, six hundred forty-nine thousand, seven hundred eighteen".