642757 has 8 divisors (see below), whose sum is σ = 671832. Its totient is φ = 614400.

The previous prime is 642739. The next prime is 642769. The reversal of 642757 is 757246.

It can be written as a sum of positive squares in 4 ways, for example, as 12321 + 630436 = 111^2 + 794^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 642757 - 2¹⁵ = 609989 is a prime.

It is a super-2 number, since 2×642757² = 826273122098, which contains 22 as substring.

It is a d-powerful number, because it can be written as 6³ + 4⁴ + 7³ + 2¹⁹ + 5 + 7⁶ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642737) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2373 + ... + 2629.

It is an arithmetic number, because the mean of its divisors is an integer number (83979).

2⁶⁴²⁷⁵⁷ is an apocalyptic number.

It is an amenable number.

642757 is a deficient number, since it is larger than the sum of its proper divisors (29075).

642757 is a wasteful number, since it uses less digits than its factorization.

642757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359.

The product of its digits is 11760, while the sum is 31.

The square root of 642757 is about 801.7212732615. The cubic root of 642757 is about 86.3009556772.

The spelling of 642757 in words is "six hundred forty-two thousand, seven hundred fifty-seven".