81301968 has 120 divisors (see below), whose sum is σ = 257546016. Its totient is φ = 24624000.

The previous prime is 81301951. The next prime is 81301991. The reversal of 81301968 is 86910318.

It is a super-2 number, since 2×81301968² = 13220020001346048, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent 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 23 ways as a sum of consecutive naturals, for example, 41818 + ... + 43718.

Almost surely, 2^81301968 is an apocalyptic number.

81301968 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

81301968 is the 5703-rd heptagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81301968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128773008).

81301968 is an abundant number, since it is smaller than the sum of its proper divisors (176244048).

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

81301968 is a wasteful number, since it uses less digits than its factorization.

81301968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1935 (or 1917 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81301968 is about 9016.7603938443. The cubic root of 81301968 is about 433.2118749670.

The spelling of 81301968 in words is "eighty-one million, three hundred one thousand, nine hundred sixty-eight".