71168951981 has 4 divisors (see below), whose sum is σ = 71171722464. Its totient is φ = 71166181500.

The previous prime is 71168951951. The next prime is 71168951983. The reversal of 71168951981 is 18915986117.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71168951981 is a prime.

It is a super-2 number, since 2×71168951981² (a number of 23 digits) 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 (71168951983) 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 3 ways as a sum of consecutive naturals, for example, 1346345 + ... + 1398206.

It is an arithmetic number, because the mean of its divisors is an integer number (17792930616).

Almost surely, 2^71168951981 is an apocalyptic number.

It is an amenable number.

71168951981 is a deficient number, since it is larger than the sum of its proper divisors (2770483).

71168951981 is a wasteful number, since it uses less digits than its factorization.

71168951981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2770482.

The product of its digits is 1088640, while the sum is 56.

The spelling of 71168951981 in words is "seventy-one billion, one hundred sixty-eight million, nine hundred fifty-one thousand, nine hundred eighty-one".