81212212 has 12 divisors (see below), whose sum is σ = 142796416. Its totient is φ = 40413240.

The previous prime is 81212207. The next prime is 81212221. The reversal of 81212212 is 21221218.

It is a self number, because there is not a number n which added to its sum of digits gives 81212212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47268 + ... + 48955.

Almost surely, 2^81212212 is an apocalyptic number.

It is an amenable number.

81212212 is a deficient number, since it is larger than the sum of its proper divisors (61584204).

81212212 is a wasteful number, since it uses less digits than its factorization.

81212212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96438 (or 96436 counting only the distinct ones).

The product of its digits is 128, while the sum is 19.

The square root of 81212212 is about 9011.7818437865. The cubic root of 81212212 is about 433.0523967336.

The spelling of 81212212 in words is "eighty-one million, two hundred twelve thousand, two hundred twelve".