81733409 has 2 divisors, whose sum is σ = 81733410. Its totient is φ = 81733408.

The previous prime is 81733363. The next prime is 81733427. The reversal of 81733409 is 90433718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61230625 + 20502784 = 7825^2 + 4528^2 .

It is a cyclic number.

It is not a de Polignac number, because 81733409 - 2¹² = 81729313 is a prime.

It is a super-2 number, since 2×81733409² = 13360700293522562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81733429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40866704 + 40866705.

It is an arithmetic number, because the mean of its divisors is an integer number (40866705).

Almost surely, 2^81733409 is an apocalyptic number.

It is an amenable number.

81733409 is a deficient number, since it is larger than the sum of its proper divisors (1).

81733409 is an equidigital number, since it uses as much as digits as its factorization.

81733409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 81733409 is about 9040.6531290610. The cubic root of 81733409 is about 433.9768245604.

The spelling of 81733409 in words is "eighty-one million, seven hundred thirty-three thousand, four hundred nine".