61566 has 16 divisors (see below), whose sum is σ = 127488. Its totient is φ = 19800.

The previous prime is 61561. The next prime is 61583. The reversal of 61566 is 66516.

It is an Ulam number.

It is a house number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21 + ... + 351.

It is an arithmetic number, because the mean of its divisors is an integer number (7968).

2⁶¹⁵⁶⁶ is an apocalyptic number.

61566 is an abundant number, since it is smaller than the sum of its proper divisors (65922).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (63744).

61566 is a wasteful number, since it uses less digits than its factorization.

61566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 367.

The product of its digits is 1080, while the sum is 24.

The square root of 61566 is about 248.1249685139. The cubic root of 61566 is about 39.4863489654.

Subtracting 61566 from its reverse (66516), we obtain a triangular number (4950 = T₉₉).

The spelling of 61566 in words is "sixty-one thousand, five hundred sixty-six".