646541 has 4 divisors (see below), whose sum is σ = 738912. Its totient is φ = 554172.

The previous prime is 646537. The next prime is 646543. The reversal of 646541 is 145646.

It is a happy number.

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: 145646 = 2 ⋅72823.

It is a cyclic number.

It is not a de Polignac number, because 646541 - 2² = 646537 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 646541.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646543) 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, 46175 + ... + 46188.

It is an arithmetic number, because the mean of its divisors is an integer number (184728).

2⁶⁴⁶⁵⁴¹ is an apocalyptic number.

It is an amenable number.

646541 is a deficient number, since it is larger than the sum of its proper divisors (92371).

646541 is an equidigital number, since it uses as much as digits as its factorization.

646541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92370.

The product of its digits is 2880, while the sum is 26.

The square root of 646541 is about 804.0777325607. The cubic root of 646541 is about 86.4699796701.

The spelling of 646541 in words is "six hundred forty-six thousand, five hundred forty-one".