71383981 has 4 divisors (see below), whose sum is σ = 71401500. Its totient is φ = 71366464.

The previous prime is 71383967. The next prime is 71384017. The reversal of 71383981 is 18938317.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18938317 = 73 ⋅259429.

It can be written as a sum of positive squares in 2 ways, for example, as 40525956 + 30858025 = 6366^2 + 5555^2 .

It is a cyclic number.

It is not a de Polignac number, because 71383981 - 2⁹ = 71383469 is a prime.

It is a super-2 number, since 2×71383981² = 10191345486816722, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71383381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 915 + ... + 11983.

It is an arithmetic number, because the mean of its divisors is an integer number (17850375).

Almost surely, 2^71383981 is an apocalyptic number.

It is an amenable number.

71383981 is a deficient number, since it is larger than the sum of its proper divisors (17519).

71383981 is a wasteful number, since it uses less digits than its factorization.

71383981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17518.

The product of its digits is 36288, while the sum is 40.

The square root of 71383981 is about 8448.9041301224. The cubic root of 71383981 is about 414.8269099623.

The spelling of 71383981 in words is "seventy-one million, three hundred eighty-three thousand, nine hundred eighty-one".