81829320 has 64 divisors (see below), whose sum is σ = 247821120. Its totient is φ = 21613824.

The previous prime is 81829273. The next prime is 81829327. The reversal of 81829320 is 2392818.

It is a super-2 number, since 2×81829320² = 13392075223324800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81829327) 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, 9654 + ... + 16026.

It is an arithmetic number, because the mean of its divisors is an integer number (3872205).

Almost surely, 2^81829320 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 81829320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123910560).

81829320 is an abundant number, since it is smaller than the sum of its proper divisors (165991800).

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

81829320 is a wasteful number, since it uses less digits than its factorization.

81829320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6494 (or 6490 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 81829320 is about 9045.9560025461. The cubic root of 81829320 is about 434.1465098877.

The spelling of 81829320 in words is "eighty-one million, eight hundred twenty-nine thousand, three hundred twenty".