20939496521 has 2 divisors, whose sum is σ = 20939496522. Its totient is φ = 20939496520.

The previous prime is 20939496491. The next prime is 20939496551. The reversal of 20939496521 is 12569493902.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (20939496491) and next prime (20939496551).

It can be written as a sum of positive squares in only one way, i.e., 16953342025 + 3986154496 = 130205^2 + 63136^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20939496521 is a prime.

It is a super-2 number, since 2×20939496521² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20939496521.

It is not a weakly prime, because it can be changed into another prime (20939496551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10469748260 + 10469748261.

It is an arithmetic number, because the mean of its divisors is an integer number (10469748261).

Almost surely, 2^20939496521 is an apocalyptic number.

It is an amenable number.

20939496521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20939496521 is an equidigital number, since it uses as much as digits as its factorization.

20939496521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1049760, while the sum is 50.

The spelling of 20939496521 in words is "twenty billion, nine hundred thirty-nine million, four hundred ninety-six thousand, five hundred twenty-one".