81930 has 16 divisors (see below), whose sum is σ = 196704. Its totient is φ = 21840.

The previous prime is 81929. The next prime is 81931. The reversal of 81930 is 3918.

81930 = 126² + 127² + ... + 130².

It is an interprime number because it is at equal distance from previous prime (81929) and next prime (81931).

It is a Curzon number.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 81897 and 81906.

It is not an unprimeable number, because it can be changed into a prime (81931) 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, 1336 + ... + 1395.

It is an arithmetic number, because the mean of its divisors is an integer number (12294).

2⁸¹⁹³⁰ is an apocalyptic number.

81930 is an abundant number, since it is smaller than the sum of its proper divisors (114774).

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 (98352).

81930 is a wasteful number, since it uses less digits than its factorization.

81930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2741.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 81930 is about 286.2341698680. The cubic root of 81930 is about 43.4324489926.

The spelling of 81930 in words is "eighty-one thousand, nine hundred thirty".