81921835 has 16 divisors (see below), whose sum is σ = 101225376. Its totient is φ = 63618048.

The previous prime is 81921797. The next prime is 81921857. The reversal of 81921835 is 53812918.

It is a cyclic number.

It is not a de Polignac number, because 81921835 - 2²¹ = 79824683 is a prime.

It is a super-2 number, since 2×81921835² = 13422374099534450, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81921794 and 81921803.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24112 + ... + 27298.

It is an arithmetic number, because the mean of its divisors is an integer number (6326586).

Almost surely, 2^81921835 is an apocalyptic number.

81921835 is a deficient number, since it is larger than the sum of its proper divisors (19303541).

81921835 is a wasteful number, since it uses less digits than its factorization.

81921835 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3342.

The product of its digits is 17280, while the sum is 37.

The square root of 81921835 is about 9051.0681690064. The cubic root of 81921835 is about 434.3100614411.

The spelling of 81921835 in words is "eighty-one million, nine hundred twenty-one thousand, eight hundred thirty-five".