81029999 has 2 divisors, whose sum is σ = 81030000. Its totient is φ = 81029998.

The previous prime is 81029987. The next prime is 81030011. The reversal of 81029999 is 99992018.

It is a balanced prime because it is at equal distance from previous prime (81029987) and next prime (81030011).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81029999 is a prime.

81029999 is a modest number, since divided by 9999 gives 8102 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81029909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40514999 + 40515000.

It is an arithmetic number, because the mean of its divisors is an integer number (40515000).

Almost surely, 2^81029999 is an apocalyptic number.

81029999 is a deficient number, since it is larger than the sum of its proper divisors (1).

81029999 is an equidigital number, since it uses as much as digits as its factorization.

81029999 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 104976, while the sum is 47.

The square root of 81029999 is about 9001.6664568290. Note that the first 3 decimals coincide. The cubic root of 81029999 is about 432.7282793696.

It can be divided in two parts, 81029 and 999, that added together give a palindrome (82028).

The spelling of 81029999 in words is "eighty-one million, twenty-nine thousand, nine hundred ninety-nine".