81401 has 2 divisors, whose sum is σ = 81402. Its totient is φ = 81400.

The previous prime is 81373. The next prime is 81409. The reversal of 81401 is 10418.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75625 + 5776 = 275^2 + 76^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81401 is a prime.

It is a super-2 number, since 2×81401² = 13252245602, which contains 22 as substring.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 81401.

It is not a weakly prime, because it can be changed into another prime (81409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700 + 40701.

It is an arithmetic number, because the mean of its divisors is an integer number (40701).

2⁸¹⁴⁰¹ is an apocalyptic number.

It is an amenable number.

81401 is a deficient number, since it is larger than the sum of its proper divisors (1).

81401 is an equidigital number, since it uses as much as digits as its factorization.

81401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 81401 is about 285.3086048475. The cubic root of 81401 is about 43.3387698636.

Adding to 81401 its reverse (10418), we get a palindrome (91819).

The spelling of 81401 in words is "eighty-one thousand, four hundred one".