642057257 has 2 divisors, whose sum is σ = 642057258. Its totient is φ = 642057256.

The previous prime is 642057239. The next prime is 642057277. The reversal of 642057257 is 752750246.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 351150121 + 290907136 = 18739^2 + 17056^2 .

It is a cyclic number.

It is not a de Polignac number, because 642057257 - 2¹⁴ = 642040873 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642057257.

It is not a weakly prime, because it can be changed into another prime (642057217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321028628 + 321028629.

It is an arithmetic number, because the mean of its divisors is an integer number (321028629).

Almost surely, 2^642057257 is an apocalyptic number.

It is an amenable number.

642057257 is a deficient number, since it is larger than the sum of its proper divisors (1).

642057257 is an equidigital number, since it uses as much as digits as its factorization.

642057257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 117600, while the sum is 38.

The square root of 642057257 is about 25338.8487702184. The cubic root of 642057257 is about 862.6962687696.

The spelling of 642057257 in words is "six hundred forty-two million, fifty-seven thousand, two hundred fifty-seven".