81212193 has 16 divisors (see below), whose sum is σ = 122876160. Its totient is φ = 52988688.

The previous prime is 81212191. The next prime is 81212203. The reversal of 81212193 is 39121218.

It is not a de Polignac number, because 81212193 - 2¹ = 81212191 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81212191) 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 15 ways as a sum of consecutive naturals, for example, 30730 + ... + 33267.

It is an arithmetic number, because the mean of its divisors is an integer number (7679760).

Almost surely, 2^81212193 is an apocalyptic number.

It is an amenable number.

81212193 is a deficient number, since it is larger than the sum of its proper divisors (41663967).

81212193 is a wasteful number, since it uses less digits than its factorization.

81212193 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64053 (or 64047 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 81212193 is about 9011.7807896109. The cubic root of 81212193 is about 433.0523629620.

It can be divided in two parts, 8 and 1212193, that added together give a square (1212201 = 1101²).

The spelling of 81212193 in words is "eighty-one million, two hundred twelve thousand, one hundred ninety-three".