545681 has 4 divisors (see below), whose sum is σ = 548352. Its totient is φ = 543012.

The previous prime is 545663. The next prime is 545711. The reversal of 545681 is 186545.

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: 186545 = 5 ⋅37309.

It is a cyclic number.

It is not a de Polignac number, because 545681 - 2⁶ = 545617 is a prime.

It is a super-2 number, since 2×545681² = 595535507522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (545621) 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, 1001 + ... + 1446.

It is an arithmetic number, because the mean of its divisors is an integer number (137088).

2⁵⁴⁵⁶⁸¹ is an apocalyptic number.

It is an amenable number.

545681 is a deficient number, since it is larger than the sum of its proper divisors (2671).

545681 is a wasteful number, since it uses less digits than its factorization.

545681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2670.

The product of its digits is 4800, while the sum is 29.

The square root of 545681 is about 738.7022404190. The cubic root of 545681 is about 81.7170996740.

The spelling of 545681 in words is "five hundred forty-five thousand, six hundred eighty-one".