20521671839 has 8 divisors (see below), whose sum is σ = 21783022848. Its totient is φ = 19266342400.

The previous prime is 20521671827. The next prime is 20521671857. The reversal of 20521671839 is 93817612502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20521671839 is a prime.

It is a super-2 number, since 2×20521671839² (a number of 21 digits) contains 22 as substring.

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 20521671839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521671139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1498367 + ... + 1512000.

It is an arithmetic number, because the mean of its divisors is an integer number (2722877856).

Almost surely, 2^20521671839 is an apocalyptic number.

20521671839 is a deficient number, since it is larger than the sum of its proper divisors (1261351009).

20521671839 is a wasteful number, since it uses less digits than its factorization.

20521671839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3010785.

The product of its (nonzero) digits is 181440, while the sum is 44.

The spelling of 20521671839 in words is "twenty billion, five hundred twenty-one million, six hundred seventy-one thousand, eight hundred thirty-nine".