642451 has 4 divisors (see below), whose sum is σ = 653400. Its totient is φ = 631504.

The previous prime is 642427. The next prime is 642457. The reversal of 642451 is 154246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 642451 - 2⁵ = 642419 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (642457) 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 3 ways as a sum of consecutive naturals, for example, 5386 + ... + 5503.

It is an arithmetic number, because the mean of its divisors is an integer number (163350).

2⁶⁴²⁴⁵¹ is an apocalyptic number.

642451 is a deficient number, since it is larger than the sum of its proper divisors (10949).

642451 is a wasteful number, since it uses less digits than its factorization.

642451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10948.

The product of its digits is 960, while the sum is 22.

The square root of 642451 is about 801.5304111511. The cubic root of 642451 is about 86.2872582850.

Adding to 642451 its reverse (154246), we get a palindrome (796697).

It can be divided in two parts, 64245 and 1, that added together give a palindrome (64246).

The spelling of 642451 in words is "six hundred forty-two thousand, four hundred fifty-one".