81906798 has 8 divisors (see below), whose sum is σ = 163813608. Its totient is φ = 27302264.

The previous prime is 81906719. The next prime is 81906823. The reversal of 81906798 is 89760918.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

81906798 is an admirable number.

It is a super-2 number, since 2×81906798² = 13417447117225608, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6825561 + ... + 6825572.

It is an arithmetic number, because the mean of its divisors is an integer number (20476701).

Almost surely, 2^81906798 is an apocalyptic number.

81906798 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81906798 is a wasteful number, since it uses less digits than its factorization.

81906798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13651138.

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 81906798 is about 9050.2374554483. The cubic root of 81906798 is about 434.2834868410.

The spelling of 81906798 in words is "eighty-one million, nine hundred six thousand, seven hundred ninety-eight".