642241751 has 4 divisors (see below), whose sum is σ = 643647552. Its totient is φ = 640835952.

The previous prime is 642241681. The next prime is 642241783. The reversal of 642241751 is 157142246.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 157142246 = 2 ⋅78571123.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642241751 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642241051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 702215 + ... + 703128.

It is an arithmetic number, because the mean of its divisors is an integer number (160911888).

Almost surely, 2^642241751 is an apocalyptic number.

642241751 is a deficient number, since it is larger than the sum of its proper divisors (1405801).

642241751 is a wasteful number, since it uses less digits than its factorization.

642241751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1405800.

The product of its digits is 13440, while the sum is 32.

The square root of 642241751 is about 25342.4890450800. The cubic root of 642241751 is about 862.7788922642.

Adding to 642241751 its reverse (157142246), we get a palindrome (799383997).

The spelling of 642241751 in words is "six hundred forty-two million, two hundred forty-one thousand, seven hundred fifty-one".