61881 has 4 divisors (see below), whose sum is σ = 82512. Its totient is φ = 41252.

The previous prime is 61879. The next prime is 61909. The reversal of 61881 is 18816.

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.

It is a cyclic number.

It is not a de Polignac number, because 61881 - 2¹ = 61879 is a prime.

It is a super-2 number, since 2×61881² = 7658516322, which contains 22 as substring.

It is a D-number.

61881 is a lucky number.

It is a nialpdrome in base 13.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 61881.

It is not an unprimeable number, because it can be changed into a prime (61861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10311 + ... + 10316.

It is an arithmetic number, because the mean of its divisors is an integer number (20628).

2⁶¹⁸⁸¹ is an apocalyptic number.

It is an amenable number.

61881 is a deficient number, since it is larger than the sum of its proper divisors (20631).

61881 is a wasteful number, since it uses less digits than its factorization.

61881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20630.

The product of its digits is 384, while the sum is 24.

The square root of 61881 is about 248.7589194381. The cubic root of 61881 is about 39.5535778842.

The spelling of 61881 in words is "sixty-one thousand, eight hundred eighty-one".