81263898 has 40 divisors (see below), whose sum is σ = 184833792. Its totient is φ = 26680104.

The previous prime is 81263881. The next prime is 81263909. The reversal of 81263898 is 89836218.

81263898 is a `hidden beast` number, since 8 + 1 + 2 + 638 + 9 + 8 = 666.

It is a super-2 number, since 2×81263898² = 13207642236308808, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7111 + ... + 14597.

Almost surely, 2^81263898 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81263898, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92416896).

81263898 is an abundant number, since it is smaller than the sum of its proper divisors (103569894).

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

81263898 is a wasteful number, since it uses less digits than its factorization.

81263898 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7568 (or 7559 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 81263898 is about 9014.6490780285. The cubic root of 81263898 is about 433.1442466288.

The spelling of 81263898 in words is "eighty-one million, two hundred sixty-three thousand, eight hundred ninety-eight".