642452989 has 2 divisors, whose sum is σ = 642452990. Its totient is φ = 642452988.

The previous prime is 642452971. The next prime is 642452999. The reversal of 642452989 is 989254246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 471628089 + 170824900 = 21717^2 + 13070^2 .

It is a cyclic number.

It is not a de Polignac number, because 642452989 - 2⁷ = 642452861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642452929) 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 as a sum of consecutive naturals, namely, 321226494 + 321226495.

It is an arithmetic number, because the mean of its divisors is an integer number (321226495).

Almost surely, 2^642452989 is an apocalyptic number.

It is an amenable number.

642452989 is a deficient number, since it is larger than the sum of its proper divisors (1).

642452989 is an equidigital number, since it uses as much as digits as its factorization.

642452989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1244160, while the sum is 49.

The square root of 642452989 is about 25346.6563672608. The cubic root of 642452989 is about 862.8734733207.

The spelling of 642452989 in words is "six hundred forty-two million, four hundred fifty-two thousand, nine hundred eighty-nine".