642336389 has 4 divisors (see below), whose sum is σ = 642395424. Its totient is φ = 642277356.

The previous prime is 642336377. The next prime is 642336403. The reversal of 642336389 is 983633246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 983633246 = 2 ⋅491816623.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642336389 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 (642336349) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7937 + ... + 36710.

It is an arithmetic number, because the mean of its divisors is an integer number (160598856).

Almost surely, 2^642336389 is an apocalyptic number.

It is an amenable number.

642336389 is a deficient number, since it is larger than the sum of its proper divisors (59035).

642336389 is a wasteful number, since it uses less digits than its factorization.

642336389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59034.

The product of its digits is 559872, while the sum is 44.

The square root of 642336389 is about 25344.3561567462. The cubic root of 642336389 is about 862.8212686530.

The spelling of 642336389 in words is "six hundred forty-two million, three hundred thirty-six thousand, three hundred eighty-nine".