61812 has 36 divisors (see below), whose sum is σ = 167076. Its totient is φ = 19200.

The previous prime is 61781. The next prime is 61813. The reversal of 61812 is 21816.

It can be written as a sum of positive squares in 2 ways, for example, as 54756 + 7056 = 234^2 + 84^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an alternating number because its digits alternate between even and odd.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61813) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 562 + ... + 662.

It is an arithmetic number, because the mean of its divisors is an integer number (4641).

2⁶¹⁸¹² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83538).

61812 is an abundant number, since it is smaller than the sum of its proper divisors (105264).

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

61812 is a wasteful number, since it uses less digits than its factorization.

61812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 123 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 61812 is about 248.6201922612. The cubic root of 61812 is about 39.5388710981.

Subtracting from 61812 its product of digits (96), we obtain a palindrome (61716).

It can be divided in two parts, 618 and 12, that added together give a triangular number (630 = T₃₅).

The spelling of 61812 in words is "sixty-one thousand, eight hundred twelve".