71981247 has 32 divisors (see below), whose sum is σ = 110315520. Its totient is φ = 41356800.

The previous prime is 71981233. The next prime is 71981251. The reversal of 71981247 is 74218917.

It is not a de Polignac number, because 71981247 - 2⁸ = 71980991 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71981207) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 99754 + ... + 100472.

It is an arithmetic number, because the mean of its divisors is an integer number (3447360).

Almost surely, 2^71981247 is an apocalyptic number.

71981247 is a deficient number, since it is larger than the sum of its proper divisors (38334273).

71981247 is a wasteful number, since it uses less digits than its factorization.

71981247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 903.

The product of its digits is 28224, while the sum is 39.

The square root of 71981247 is about 8484.1762711533. The cubic root of 71981247 is about 415.9806431298.

Subtracting 71981247 from its reverse (74218917), we obtain a triangular number (2237670 = T₂₁₁₅).

The spelling of 71981247 in words is "seventy-one million, nine hundred eighty-one thousand, two hundred forty-seven".