642735571 has 2 divisors, whose sum is σ = 642735572. Its totient is φ = 642735570.

The previous prime is 642735563. The next prime is 642735593. The reversal of 642735571 is 175537246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642735571 - 2³ = 642735563 is a prime.

It is not a weakly prime, because it can be changed into another prime (642735551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321367785 + 321367786.

It is an arithmetic number, because the mean of its divisors is an integer number (321367786).

Almost surely, 2^642735571 is an apocalyptic number.

642735571 is a deficient number, since it is larger than the sum of its proper divisors (1).

642735571 is an equidigital number, since it uses as much as digits as its factorization.

642735571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 176400, while the sum is 40.

The square root of 642735571 is about 25352.2300991451. The cubic root of 642735571 is about 862.9999659850. Note that the first 4 decimals are identical.

The spelling of 642735571 in words is "six hundred forty-two million, seven hundred thirty-five thousand, five hundred seventy-one".