642536 has 8 divisors (see below), whose sum is σ = 1204770. Its totient is φ = 321264.

The previous prime is 642533. The next prime is 642547. The reversal of 642536 is 635246.

It can be written as a sum of positive squares in only one way, i.e., 630436 + 12100 = 794^2 + 110^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×642536² = 825705022592, which contains 22 as substring.

It is an Ulam number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642536.

It is not an unprimeable number, because it can be changed into a prime (642533) 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 as a sum of consecutive naturals, namely, 40151 + ... + 40166.

2⁶⁴²⁵³⁶ is an apocalyptic number.

It is an amenable number.

642536 is a deficient number, since it is larger than the sum of its proper divisors (562234).

642536 is a wasteful number, since it uses less digits than its factorization.

642536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80323 (or 80319 counting only the distinct ones).

The product of its digits is 4320, while the sum is 26.

The square root of 642536 is about 801.5834329625. The cubic root of 642536 is about 86.2910635524.

The spelling of 642536 in words is "six hundred forty-two thousand, five hundred thirty-six".