81212620 has 12 divisors (see below), whose sum is σ = 170546544. Its totient is φ = 32485040.

The previous prime is 81212603. The next prime is 81212623. The reversal of 81212620 is 2621218.

It is a junction number, because it is equal to n+sod(n) for n = 81212591 and 81212600.

It is not an unprimeable number, because it can be changed into a prime (81212623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030296 + ... + 2030335.

It is an arithmetic number, because the mean of its divisors is an integer number (14212212).

Almost surely, 2^81212620 is an apocalyptic number.

It is an amenable number.

81212620 is an abundant number, since it is smaller than the sum of its proper divisors (89333924).

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

81212620 is a wasteful number, since it uses less digits than its factorization.

81212620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4060640 (or 4060638 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 22.

The square root of 81212620 is about 9011.8044807907. The cubic root of 81212620 is about 433.0531219328.

Adding to 81212620 its reverse (2621218), we get a palindrome (83833838).

The spelling of 81212620 in words is "eighty-one million, two hundred twelve thousand, six hundred twenty".