81029723 has 2 divisors, whose sum is σ = 81029724. Its totient is φ = 81029722.

The previous prime is 81029719. The next prime is 81029749. The reversal of 81029723 is 32792018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81029723 - 2² = 81029719 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81029723.

It is not a weakly prime, because it can be changed into another prime (81029323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40514861 + 40514862.

It is an arithmetic number, because the mean of its divisors is an integer number (40514862).

Almost surely, 2^81029723 is an apocalyptic number.

81029723 is a deficient number, since it is larger than the sum of its proper divisors (1).

81029723 is an equidigital number, since it uses as much as digits as its factorization.

81029723 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 81029723 is about 9001.6511263212. The cubic root of 81029723 is about 432.7277880571.

The spelling of 81029723 in words is "eighty-one million, twenty-nine thousand, seven hundred twenty-three".