345661 has 4 divisors (see below), whose sum is σ = 366012. Its totient is φ = 325312.

The previous prime is 345659. The next prime is 345673. The reversal of 345661 is 166543.

345661 = 56² + 57² + ... + 106².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 308025 + 37636 = 555^2 + 194^2 .

It is not a de Polignac number, because 345661 - 2¹ = 345659 is a prime.

It is a d-powerful number, because it can be written as 3³ + 4⁸ + 6² + 5³ + 6⁷ + 1 .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (345601) 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, 10150 + ... + 10183.

It is an arithmetic number, because the mean of its divisors is an integer number (91503).

2³⁴⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

345661 is a deficient number, since it is larger than the sum of its proper divisors (20351).

345661 is a wasteful number, since it uses less digits than its factorization.

345661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20350.

The product of its digits is 2160, while the sum is 25.

The square root of 345661 is about 587.9294175324. The cubic root of 345661 is about 70.1805542956.

The spelling of 345661 in words is "three hundred forty-five thousand, six hundred sixty-one".