81682021 has 8 divisors (see below), whose sum is σ = 82987200. Its totient is φ = 80381280.

The previous prime is 81681961. The next prime is 81682031. The reversal of 81682021 is 12028618.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81682021 - 2¹¹ = 81679973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81682031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71785 + ... + 72913.

It is an arithmetic number, because the mean of its divisors is an integer number (10373400).

Almost surely, 2^81682021 is an apocalyptic number.

It is an amenable number.

81682021 is a deficient number, since it is larger than the sum of its proper divisors (1305179).

81682021 is a wasteful number, since it uses less digits than its factorization.

81682021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2219.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 81682021 is about 9037.8106308995. The cubic root of 81682021 is about 433.8858545122.

The spelling of 81682021 in words is "eighty-one million, six hundred eighty-two thousand, twenty-one".