642517 has 2 divisors, whose sum is σ = 642518. Its totient is φ = 642516.

The previous prime is 642487. The next prime is 642527. The reversal of 642517 is 715246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 461041 + 181476 = 679^2 + 426^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642517 is a prime.

642517 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 642491 and 642500.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642527) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321258 + 321259.

It is an arithmetic number, because the mean of its divisors is an integer number (321259).

2⁶⁴²⁵¹⁷ is an apocalyptic number.

It is an amenable number.

642517 is a deficient number, since it is larger than the sum of its proper divisors (1).

642517 is an equidigital number, since it uses as much as digits as its factorization.

642517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 642517 is about 801.5715813326. The cubic root of 642517 is about 86.2902129923.

The spelling of 642517 in words is "six hundred forty-two thousand, five hundred seventeen".