81420558 has 16 divisors (see below), whose sum is σ = 163232976. Its totient is φ = 27074880.

The previous prime is 81420557. The next prime is 81420569. The reversal of 81420558 is 85502418.

It is a super-3 number, since 3×81420558³ (a number of 25 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81420553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13591 + ... + 18642.

It is an arithmetic number, because the mean of its divisors is an integer number (10202061).

Almost surely, 2^81420558 is an apocalyptic number.

81420558 is an abundant number, since it is smaller than the sum of its proper divisors (81812418).

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

81420558 is a wasteful number, since it uses less digits than its factorization.

81420558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32659.

The product of its (nonzero) digits is 12800, while the sum is 33.

The square root of 81420558 is about 9023.3340844723. The cubic root of 81420558 is about 433.4224054900.

The spelling of 81420558 in words is "eighty-one million, four hundred twenty thousand, five hundred fifty-eight".