81285426 has 12 divisors (see below), whose sum is σ = 176118462. Its totient is φ = 27095136.

The previous prime is 81285409. The next prime is 81285443. The reversal of 81285426 is 62458218.

It is an interprime number because it is at equal distance from previous prime (81285409) and next prime (81285443).

It can be written as a sum of positive squares in only one way, i.e., 49914225 + 31371201 = 7065^2 + 5601^2 .

It is a super-3 number, since 3×81285426³ (a number of 25 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2257911 + ... + 2257946.

Almost surely, 2^81285426 is an apocalyptic number.

81285426 is an abundant number, since it is smaller than the sum of its proper divisors (94833036).

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

81285426 is a wasteful number, since it uses less digits than its factorization.

81285426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4515865 (or 4515862 counting only the distinct ones).

The product of its digits is 30720, while the sum is 36.

The square root of 81285426 is about 9015.8430554219. The cubic root of 81285426 is about 433.1824920091.

The spelling of 81285426 in words is "eighty-one million, two hundred eighty-five thousand, four hundred twenty-six".