642470989 has 4 divisors (see below), whose sum is σ = 642532924. Its totient is φ = 642409056.

The previous prime is 642470963. The next prime is 642470993. The reversal of 642470989 is 989074246.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 255680100 + 386790889 = 15990^2 + 19667^2 .

It is a cyclic number.

It is not a de Polignac number, because 642470989 - 2¹¹ = 642468941 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 (642470909) 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, 11202 + ... + 37555.

It is an arithmetic number, because the mean of its divisors is an integer number (160633231).

Almost surely, 2^642470989 is an apocalyptic number.

It is an amenable number.

642470989 is a deficient number, since it is larger than the sum of its proper divisors (61935).

642470989 is a wasteful number, since it uses less digits than its factorization.

642470989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61934.

The product of its (nonzero) digits is 870912, while the sum is 49.

The square root of 642470989 is about 25347.0114411936. The cubic root of 642470989 is about 862.8815317975.

The spelling of 642470989 in words is "six hundred forty-two million, four hundred seventy thousand, nine hundred eighty-nine".