81629285 has 8 divisors (see below), whose sum is σ = 99561336. Its totient is φ = 64232640.

The previous prime is 81629281. The next prime is 81629411. The reversal of 81629285 is 58292618.

It can be written as a sum of positive squares in 4 ways, for example, as 16129 + 81613156 = 127^2 + 9034^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81629285 - 2² = 81629281 is a prime.

It is a super-2 number, since 2×81629285² = 13326680339222450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81629281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 133514 + ... + 134123.

It is an arithmetic number, because the mean of its divisors is an integer number (12445167).

Almost surely, 2^81629285 is an apocalyptic number.

It is an amenable number.

81629285 is a deficient number, since it is larger than the sum of its proper divisors (17932051).

81629285 is a wasteful number, since it uses less digits than its factorization.

81629285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267703.

The product of its digits is 69120, while the sum is 41.

The square root of 81629285 is about 9034.8926390965. The cubic root of 81629285 is about 433.7924584780.

The spelling of 81629285 in words is "eighty-one million, six hundred twenty-nine thousand, two hundred eighty-five".