642642547 has 2 divisors, whose sum is σ = 642642548. Its totient is φ = 642642546.

The previous prime is 642642521. The next prime is 642642571. The reversal of 642642547 is 745246246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642642547 - 2⁷ = 642642419 is a prime.

It is not a weakly prime, because it can be changed into another prime (642642577) 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, 321321273 + 321321274.

It is an arithmetic number, because the mean of its divisors is an integer number (321321274).

Almost surely, 2^642642547 is an apocalyptic number.

642642547 is a deficient number, since it is larger than the sum of its proper divisors (1).

642642547 is an equidigital number, since it uses as much as digits as its factorization.

642642547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 40.

The square root of 642642547 is about 25350.3954012556. The cubic root of 642642547 is about 862.9583295870.

The spelling of 642642547 in words is "six hundred forty-two million, six hundred forty-two thousand, five hundred forty-seven".