142561 has 4 divisors (see below), whose sum is σ = 146452. Its totient is φ = 138672.

The previous prime is 142559. The next prime is 142567. The reversal of 142561 is 165241.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165241 = 149 ⋅1109.

It can be written as a sum of positive squares in 2 ways, for example, as 136161 + 6400 = 369^2 + 80^2 .

It is a cyclic number.

It is not a de Polignac number, because 142561 - 2¹ = 142559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (142567) 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, 1890 + ... + 1963.

It is an arithmetic number, because the mean of its divisors is an integer number (36613).

2¹⁴²⁵⁶¹ is an apocalyptic number.

It is an amenable number.

142561 is a deficient number, since it is larger than the sum of its proper divisors (3891).

142561 is an equidigital number, since it uses as much as digits as its factorization.

142561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3890.

The product of its digits is 240, while the sum is 19.

The square root of 142561 is about 377.5725095925. The cubic root of 142561 is about 52.2396482930.

It can be divided in two parts, 142 and 561, that added together give a triangular number (703 = T₃₇).

The spelling of 142561 in words is "one hundred forty-two thousand, five hundred sixty-one".