81820098 has 64 divisors (see below), whose sum is σ = 192906240. Its totient is φ = 25660800.

The previous prime is 81820073. The next prime is 81820117. The reversal of 81820098 is 89002818.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 61278 + ... + 62598.

It is an arithmetic number, because the mean of its divisors is an integer number (3014160).

Almost surely, 2^81820098 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81820098, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (96453120).

81820098 is an abundant number, since it is smaller than the sum of its proper divisors (111086142).

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

81820098 is a wasteful number, since it uses less digits than its factorization.

81820098 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1400 (or 1394 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 81820098 is about 9045.4462576481. The cubic root of 81820098 is about 434.1302001285.

The spelling of 81820098 in words is "eighty-one million, eight hundred twenty thousand, ninety-eight".