642637718 has 4 divisors (see below), whose sum is σ = 963956580. Its totient is φ = 321318858.

The previous prime is 642637679. The next prime is 642637763. The reversal of 642637718 is 817736246.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160659428 + ... + 160659431.

It is an arithmetic number, because the mean of its divisors is an integer number (240989145).

Almost surely, 2^642637718 is an apocalyptic number.

642637718 is a deficient number, since it is larger than the sum of its proper divisors (321318862).

642637718 is a wasteful number, since it uses less digits than its factorization.

642637718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321318861.

The product of its digits is 338688, while the sum is 44.

The square root of 642637718 is about 25350.3001560139. The cubic root of 642637718 is about 862.9561680763.

It can be divided in two parts, 6426 and 37718, that added together give a palindrome (44144).

The spelling of 642637718 in words is "six hundred forty-two million, six hundred thirty-seven thousand, seven hundred eighteen".