355661 has 4 divisors (see below), whose sum is σ = 374400. Its totient is φ = 336924.

The previous prime is 355651. The next prime is 355669. The reversal of 355661 is 166553.

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: 166553 = 151 ⋅1103.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-355661 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 355661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (355669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9341 + ... + 9378.

It is an arithmetic number, because the mean of its divisors is an integer number (93600).

2³⁵⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

355661 is a deficient number, since it is larger than the sum of its proper divisors (18739).

355661 is a wasteful number, since it uses less digits than its factorization.

355661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18738.

The product of its digits is 2700, while the sum is 26.

The square root of 355661 is about 596.3732053002. The cubic root of 355661 is about 70.8509071351.

It can be divided in two parts, 35 and 5661, that multiplied together give a triangular number (198135 = T₆₂₉).

The spelling of 355661 in words is "three hundred fifty-five thousand, six hundred sixty-one".