81929898 has 12 divisors (see below), whose sum is σ = 177514818. Its totient is φ = 27309960.

The previous prime is 81929879. The next prime is 81929899. The reversal of 81929898 is 89892918.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 70006689 + 11923209 = 8367^2 + 3453^2 .

It is a super-3 number, since 3×81929898³ (a number of 25 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (81929899) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2275813 + ... + 2275848.

Almost surely, 2^81929898 is an apocalyptic number.

81929898 is an abundant number, since it is smaller than the sum of its proper divisors (95584920).

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

81929898 is a wasteful number, since it uses less digits than its factorization.

81929898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4551669 (or 4551666 counting only the distinct ones).

The product of its digits is 746496, while the sum is 54.

The square root of 81929898 is about 9051.5135750879. The cubic root of 81929898 is about 434.3243096861.

The spelling of 81929898 in words is "eighty-one million, nine hundred twenty-nine thousand, eight hundred ninety-eight".