642397 has 4 divisors (see below), whose sum is σ = 734176. Its totient is φ = 550620.

The previous prime is 642373. The next prime is 642403. The reversal of 642397 is 793246.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 793246 = 2 ⋅396623.

It is a de Polignac number, because none of the positive numbers 2^k-642397 is a prime.

It is a d-powerful number, because it can be written as 6⁷ + 4⁸ + 3¹¹ + 2¹¹ + 9² + 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 (642197) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45879 + ... + 45892.

It is an arithmetic number, because the mean of its divisors is an integer number (183544).

2⁶⁴²³⁹⁷ is an apocalyptic number.

It is an amenable number.

642397 is a deficient number, since it is larger than the sum of its proper divisors (91779).

642397 is an equidigital number, since it uses as much as digits as its factorization.

642397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91778.

The product of its digits is 9072, while the sum is 31.

The square root of 642397 is about 801.4967248841. The cubic root of 642397 is about 86.2848406466.

It can be divided in two parts, 64239 and 7, that added together give a palindrome (64246).

The spelling of 642397 in words is "six hundred forty-two thousand, three hundred ninety-seven".