71669 has 8 divisors (see below), whose sum is σ = 79800. Its totient is φ = 63936.

The previous prime is 71663. The next prime is 71671. The reversal of 71669 is 96617.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3025 + 68644 = 55^2 + 262^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 71669 - 2⁸ = 71413 is a prime.

It is a super-2 number, since 2×71669² = 10272891122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71663) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 407 + ... + 555.

It is an arithmetic number, because the mean of its divisors is an integer number (9975).

2⁷¹⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

71669 is a deficient number, since it is larger than the sum of its proper divisors (8131).

71669 is a wasteful number, since it uses less digits than its factorization.

71669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199.

The product of its digits is 2268, while the sum is 29.

The square root of 71669 is about 267.7106647110. The cubic root of 71669 is about 41.5378278015.

Adding to 71669 its product of digits (2268), we get a palindrome (73937).

The spelling of 71669 in words is "seventy-one thousand, six hundred sixty-nine".