83921681 has 16 divisors (see below), whose sum is σ = 89430528. Its totient is φ = 78624000.

The previous prime is 83921671. The next prime is 83921699. The reversal of 83921681 is 18612938.

It is a cyclic number.

It is not a de Polignac number, because 83921681 - 2²² = 79727377 is a prime.

It is a super-2 number, since 2×83921681² = 14085697083731522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (83921671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 209081 + ... + 209481.

It is an arithmetic number, because the mean of its divisors is an integer number (5589408).

Almost surely, 2^83921681 is an apocalyptic number.

It is an amenable number.

83921681 is a deficient number, since it is larger than the sum of its proper divisors (5508847).

83921681 is a wasteful number, since it uses less digits than its factorization.

83921681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 632.

The product of its digits is 20736, while the sum is 38.

The square root of 83921681 is about 9160.8777417887. The cubic root of 83921681 is about 437.8157607287.

The spelling of 83921681 in words is "eighty-three million, nine hundred twenty-one thousand, six hundred eighty-one".