81682020 has 216 divisors, whose sum is σ = 299767104. Its totient is φ = 18670176.

The previous prime is 81681961. The next prime is 81682031. The reversal of 81682020 is 2028618.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 11668857 + ... + 11668863.

Almost surely, 2^81682020 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 81682020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149883552).

81682020 is an abundant number, since it is smaller than the sum of its proper divisors (218085084).

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

81682020 is an frugal number, since it uses more digits than its factorization.

81682020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81682020 is about 9037.8105755764. The cubic root of 81682020 is about 433.8858527415.

The spelling of 81682020 in words is "eighty-one million, six hundred eighty-two thousand, twenty".