642811 has 8 divisors (see below), whose sum is σ = 698544. Its totient is φ = 588000.

The previous prime is 642809. The next prime is 642833. The reversal of 642811 is 118246.

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

It is a 5-Lehmer number, since φ(642811) divides (642811-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 642811 - 2¹ = 642809 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642871) 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, 2436 + ... + 2686.

It is an arithmetic number, because the mean of its divisors is an integer number (87318).

2⁶⁴²⁸¹¹ is an apocalyptic number.

642811 is a deficient number, since it is larger than the sum of its proper divisors (55733).

642811 is a wasteful number, since it uses less digits than its factorization.

642811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461.

The product of its digits is 384, while the sum is 22.

The square root of 642811 is about 801.7549500939. The cubic root of 642811 is about 86.3033724128.

The spelling of 642811 in words is "six hundred forty-two thousand, eight hundred eleven".