642015571 has 2 divisors, whose sum is σ = 642015572. Its totient is φ = 642015570.

The previous prime is 642015533. The next prime is 642015587. The reversal of 642015571 is 175510246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642015571 - 2²⁹ = 105144659 is a prime.

It is not a weakly prime, because it can be changed into another prime (642015371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321007785 + 321007786.

It is an arithmetic number, because the mean of its divisors is an integer number (321007786).

Almost surely, 2^642015571 is an apocalyptic number.

642015571 is a deficient number, since it is larger than the sum of its proper divisors (1).

642015571 is an equidigital number, since it uses as much as digits as its factorization.

642015571 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8400, while the sum is 31.

The square root of 642015571 is about 25338.0261859522. The cubic root of 642015571 is about 862.6775979867.

The spelling of 642015571 in words is "six hundred forty-two million, fifteen thousand, five hundred seventy-one".