561771 has 24 divisors (see below), whose sum is σ = 956384. Its totient is φ = 311040.

The previous prime is 561767. The next prime is 561787. The reversal of 561771 is 177165.

It is not a de Polignac number, because 561771 - 2² = 561767 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an Ulam number.

It is a Duffinian number.

561771 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (561761) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2211 + ... + 2451.

2⁵⁶¹⁷⁷¹ is an apocalyptic number.

561771 is a deficient number, since it is larger than the sum of its proper divisors (394613).

561771 is a wasteful number, since it uses less digits than its factorization.

561771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291 (or 288 counting only the distinct ones).

The product of its digits is 1470, while the sum is 27.

The square root of 561771 is about 749.5138424339. The cubic root of 561771 is about 82.5125049915.

It can be divided in two parts, 5 and 61771, that added together give a triangular number (61776 = T₃₅₁).

The spelling of 561771 in words is "five hundred sixty-one thousand, seven hundred seventy-one".