81214020 has 72 divisors (see below), whose sum is σ = 251026776. Its totient is φ = 21245952.

The previous prime is 81214019. The next prime is 81214027. The reversal of 81214020 is 2041218.

It can be written as a sum of positive squares in 4 ways, for example, as 37970244 + 43243776 = 6162^2 + 6576^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 81213984 and 81214002.

It is not an unprimeable number, because it can be changed into a prime (81214027) 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 23 ways as a sum of consecutive naturals, for example, 5284 + ... + 13796.

It is an arithmetic number, because the mean of its divisors is an integer number (3486483).

Almost surely, 2^81214020 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81214020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125513388).

81214020 is an abundant number, since it is smaller than the sum of its proper divisors (169812756).

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

81214020 is a wasteful number, since it uses less digits than its factorization.

81214020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8581 (or 8576 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 81214020 is about 9011.8821563534. The cubic root of 81214020 is about 433.0556103428.

Adding to 81214020 its reverse (2041218), we get a palindrome (83255238).

The spelling of 81214020 in words is "eighty-one million, two hundred fourteen thousand, twenty".