81454981 has 2 divisors, whose sum is σ = 81454982. Its totient is φ = 81454980.

The previous prime is 81454951. The next prime is 81454993. The reversal of 81454981 is 18945418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81450625 + 4356 = 9025^2 + 66^2 .

It is a cyclic number.

It is not a de Polignac number, because 81454981 - 2⁹ = 81454469 is a prime.

It is a super-2 number, since 2×81454981² = 13269827859420722, which contains 22 as substring.

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

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81454931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40727490 + 40727491.

It is an arithmetic number, because the mean of its divisors is an integer number (40727491).

Almost surely, 2^81454981 is an apocalyptic number.

It is an amenable number.

81454981 is a deficient number, since it is larger than the sum of its proper divisors (1).

81454981 is an equidigital number, since it uses as much as digits as its factorization.

81454981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 46080, while the sum is 40.

The square root of 81454981 is about 9025.2413264134. The cubic root of 81454981 is about 433.4834776882.

The spelling of 81454981 in words is "eighty-one million, four hundred fifty-four thousand, nine hundred eighty-one".