81029385 has 24 divisors (see below), whose sum is σ = 140876424. Its totient is φ = 43084800.

The previous prime is 81029359. The next prime is 81029447. The reversal of 81029385 is 58392018.

It can be written as a sum of positive squares in 4 ways, for example, as 944784 + 80084601 = 972^2 + 8949^2 .

It is not a de Polignac number, because 81029385 - 2¹⁹ = 80505097 is a prime.

It is a super-2 number, since 2×81029385² = 13131522466956450, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13335 + ... + 18435.

It is an arithmetic number, because the mean of its divisors is an integer number (5869851).

Almost surely, 2^81029385 is an apocalyptic number.

It is an amenable number.

81029385 is a deficient number, since it is larger than the sum of its proper divisors (59847039).

81029385 is a wasteful number, since it uses less digits than its factorization.

81029385 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5465 (or 5462 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 81029385 is about 9001.6323519682. The cubic root of 81029385 is about 432.7271863759.

The spelling of 81029385 in words is "eighty-one million, twenty-nine thousand, three hundred eighty-five".