27961 has 2 divisors, whose sum is σ = 27962. Its totient is φ = 27960.

The previous prime is 27953. The next prime is 27967. The reversal of 27961 is 16972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20736 + 7225 = 144^2 + 85^2 .

It is a cyclic number.

It is not a de Polignac number, because 27961 - 2³ = 27953 is a prime.

27961 is a lucky number.

It is a nialpdrome in base 15.

It is not a weakly prime, because it can be changed into another prime (27967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13980 + 13981.

It is an arithmetic number, because the mean of its divisors is an integer number (13981).

2²⁷⁹⁶¹ is an apocalyptic number.

It is an amenable number.

27961 is a deficient number, since it is larger than the sum of its proper divisors (1).

27961 is an equidigital number, since it uses as much as digits as its factorization.

27961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 756, while the sum is 25.

The square root of 27961 is about 167.2154299100. The cubic root of 27961 is about 30.3517847192.

The spelling of 27961 in words is "twenty-seven thousand, nine hundred sixty-one".