81210612 has 48 divisors (see below), whose sum is σ = 217566720. Its totient is φ = 23095392.

The previous prime is 81210601. The next prime is 81210629. The reversal of 81210612 is 21601218.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16939 + ... + 21197.

It is an arithmetic number, because the mean of its divisors is an integer number (4532640).

Almost surely, 2^81210612 is an apocalyptic number.

It is an amenable number.

81210612 is an abundant number, since it is smaller than the sum of its proper divisors (136356108).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81210612 is a wasteful number, since it uses less digits than its factorization.

81210612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4500 (or 4498 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 81210612 is about 9011.6930706721. The cubic root of 81210612 is about 433.0495527919.

The spelling of 81210612 in words is "eighty-one million, two hundred ten thousand, six hundred twelve".