66461 has 4 divisors (see below), whose sum is σ = 68124. Its totient is φ = 64800.

The previous prime is 66457. The next prime is 66463. The reversal of 66461 is 16466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16466 = 2 ⋅8233.

It can be written as a sum of positive squares in 2 ways, for example, as 24025 + 42436 = 155^2 + 206^2 .

It is a cyclic number.

It is not a de Polignac number, because 66461 - 2² = 66457 is a prime.

It is a Duffinian number.

It is a plaindrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66463) 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, 770 + ... + 851.

It is an arithmetic number, because the mean of its divisors is an integer number (17031).

2⁶⁶⁴⁶¹ is an apocalyptic number.

It is an amenable number.

66461 is a deficient number, since it is larger than the sum of its proper divisors (1663).

66461 is a wasteful number, since it uses less digits than its factorization.

66461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1662.

The product of its digits is 864, while the sum is 23.

The square root of 66461 is about 257.8003103179. The cubic root of 66461 is about 40.5062734782.

It can be divided in two parts, 664 and 61, that multiplied together give a palindrome (40504).

The spelling of 66461 in words is "sixty-six thousand, four hundred sixty-one".