642713257 has 6 divisors (see below), whose sum is σ = 645087534. Its totient is φ = 640342080.

The previous prime is 642713251. The next prime is 642713317. The reversal of 642713257 is 752317246.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 32672656 + 610040601 = 5716^2 + 24699^2 .

It is not a de Polignac number, because 642713257 - 2⁷ = 642713129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642713251) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 464707 + ... + 466087.

It is an arithmetic number, because the mean of its divisors is an integer number (107514589).

Almost surely, 2^642713257 is an apocalyptic number.

It is an amenable number.

642713257 is a deficient number, since it is larger than the sum of its proper divisors (2374277).

642713257 is an frugal number, since it uses more digits than its factorization.

642713257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3099 (or 1718 counting only the distinct ones).

The product of its digits is 70560, while the sum is 37.

The square root of 642713257 is about 25351.7900156971. The cubic root of 642713257 is about 862.9899788794.

It can be divided in two parts, 64271 and 3257, that added together give a triangular number (67528 = T₃₆₇).

The spelling of 642713257 in words is "six hundred forty-two million, seven hundred thirteen thousand, two hundred fifty-seven".