671527731821 has 4 divisors (see below), whose sum is σ = 676034629500. Its totient is φ = 667020834144.

The previous prime is 671527731793. The next prime is 671527731829. The reversal of 671527731821 is 128137725176.

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 51708486025 + 619819245796 = 227395^2 + 787286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-671527731821 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 671527731821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (671527731829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2253448616 + ... + 2253448913.

It is an arithmetic number, because the mean of its divisors is an integer number (169008657375).

Almost surely, 2^671527731821 is an apocalyptic number.

It is an amenable number.

671527731821 is a deficient number, since it is larger than the sum of its proper divisors (4506897679).

671527731821 is a wasteful number, since it uses less digits than its factorization.

671527731821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4506897678.

The product of its digits is 987840, while the sum is 50.

The spelling of 671527731821 in words is "six hundred seventy-one billion, five hundred twenty-seven million, seven hundred thirty-one thousand, eight hundred twenty-one".