642617489 has 2 divisors, whose sum is σ = 642617490. Its totient is φ = 642617488.

The previous prime is 642617473. The next prime is 642617491. The reversal of 642617489 is 984716246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 634636864 + 7980625 = 25192^2 + 2825^2 .

It is a cyclic number.

It is not a de Polignac number, because 642617489 - 2⁴ = 642617473 is a prime.

Together with 642617491, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (642617189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321308744 + 321308745.

It is an arithmetic number, because the mean of its divisors is an integer number (321308745).

Almost surely, 2^642617489 is an apocalyptic number.

It is an amenable number.

642617489 is a deficient number, since it is larger than the sum of its proper divisors (1).

642617489 is an equidigital number, since it uses as much as digits as its factorization.

642617489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 47.

The square root of 642617489 is about 25349.9011635154. The cubic root of 642617489 is about 862.9471132475.

The spelling of 642617489 in words is "six hundred forty-two million, six hundred seventeen thousand, four hundred eighty-nine".