81617441 has 2 divisors, whose sum is σ = 81617442. Its totient is φ = 81617440.

The previous prime is 81617423. The next prime is 81617443. The reversal of 81617441 is 14471618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 71757841 + 9859600 = 8471^2 + 3140^2 .

It is a cyclic number.

It is not a de Polignac number, because 81617441 - 2¹⁸ = 81355297 is a prime.

It is a super-2 number, since 2×81617441² = 13322813350776962, which contains 22 as substring.

Together with 81617443, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81617398 and 81617407.

It is not a weakly prime, because it can be changed into another prime (81617443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40808720 + 40808721.

It is an arithmetic number, because the mean of its divisors is an integer number (40808721).

Almost surely, 2^81617441 is an apocalyptic number.

It is an amenable number.

81617441 is a deficient number, since it is larger than the sum of its proper divisors (1).

81617441 is an equidigital number, since it uses as much as digits as its factorization.

81617441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5376, while the sum is 32.

The square root of 81617441 is about 9034.2371565064. The cubic root of 81617441 is about 433.7714770929.

The spelling of 81617441 in words is "eighty-one million, six hundred seventeen thousand, four hundred forty-one".