81702020 has 24 divisors (see below), whose sum is σ = 174484800. Its totient is φ = 32126432.

The previous prime is 81702013. The next prime is 81702029. The reversal of 81702020 is 2020718.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 81701983 and 81702001.

It is not an unprimeable number, because it can be changed into a prime (81702029) 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 7 ways as a sum of consecutive naturals, for example, 33440 + ... + 35799.

It is an arithmetic number, because the mean of its divisors is an integer number (7270200).

Almost surely, 2^81702020 is an apocalyptic number.

It is an amenable number.

81702020 is an abundant number, since it is smaller than the sum of its proper divisors (92782780).

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

81702020 is a wasteful number, since it uses less digits than its factorization.

81702020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69307 (or 69305 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 81702020 is about 9038.9169705225. The cubic root of 81702020 is about 433.9212624474.

Adding to 81702020 its reverse (2020718), we get a palindrome (83722738).

The spelling of 81702020 in words is "eighty-one million, seven hundred two thousand, twenty".