71947665 has 24 divisors (see below), whose sum is σ = 125821800. Its totient is φ = 38029824.

The previous prime is 71947649. The next prime is 71947669. The reversal of 71947665 is 56674917.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4822416 + 67125249 = 2196^2 + 8193^2 .

It is not a de Polignac number, because 71947665 - 2⁴ = 71947649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 71947665.

It is not an unprimeable number, because it can be changed into a prime (71947669) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1990 + ... + 12159.

It is an arithmetic number, because the mean of its divisors is an integer number (5242575).

Almost surely, 2^71947665 is an apocalyptic number.

It is an amenable number.

71947665 is a deficient number, since it is larger than the sum of its proper divisors (53874135).

71947665 is a wasteful number, since it uses less digits than its factorization.

71947665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14273 (or 14270 counting only the distinct ones).

The product of its digits is 317520, while the sum is 45.

The square root of 71947665 is about 8482.1969441885. The cubic root of 71947665 is about 415.9159427829.

It can be divided in two parts, 719 and 47665, that added together give a palindrome (48384).

The spelling of 71947665 in words is "seventy-one million, nine hundred forty-seven thousand, six hundred sixty-five".