642687 has 8 divisors (see below), whose sum is σ = 871680. Its totient is φ = 421080.

The previous prime is 642683. The next prime is 642701. The reversal of 642687 is 786246.

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

It is not a de Polignac number, because 642687 - 2² = 642683 is a prime.

It is a d-powerful number, because it can be written as 6 + 4² + 6³ + 2¹⁹ + 8³ + 7⁶ .

642687 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642687.

It is not an unprimeable number, because it can be changed into a prime (642683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1639 + ... + 1992.

It is an arithmetic number, because the mean of its divisors is an integer number (108960).

2⁶⁴²⁶⁸⁷ is an apocalyptic number.

642687 is a deficient number, since it is larger than the sum of its proper divisors (228993).

642687 is a wasteful number, since it uses less digits than its factorization.

642687 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3693.

The product of its digits is 16128, while the sum is 33.

The square root of 642687 is about 801.6776160028. The cubic root of 642687 is about 86.2978226704.

The spelling of 642687 in words is "six hundred forty-two thousand, six hundred eighty-seven".