71959661 has 4 divisors (see below), whose sum is σ = 72485052. Its totient is φ = 71434272.

The previous prime is 71959619. The next prime is 71959717. The reversal of 71959661 is 16695917.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59136100 + 12823561 = 7690^2 + 3581^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71959661 is a prime.

It is a super-2 number, since 2×71959661² = 10356385622469842, 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 (71959361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 262490 + ... + 262763.

It is an arithmetic number, because the mean of its divisors is an integer number (18121263).

Almost surely, 2^71959661 is an apocalyptic number.

It is an amenable number.

71959661 is a deficient number, since it is larger than the sum of its proper divisors (525391).

71959661 is a wasteful number, since it uses less digits than its factorization.

71959661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 525390.

The product of its digits is 102060, while the sum is 44.

The square root of 71959661 is about 8482.9040428382. The cubic root of 71959661 is about 415.9390570395.

The spelling of 71959661 in words is "seventy-one million, nine hundred fifty-nine thousand, six hundred sixty-one".