20834978621 has 2 divisors, whose sum is σ = 20834978622. Its totient is φ = 20834978620.

The previous prime is 20834978611. The next prime is 20834978623. The reversal of 20834978621 is 12687943802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19241851225 + 1593127396 = 138715^2 + 39914^2 .

It is a cyclic number.

It is not a de Polignac number, because 20834978621 - 2⁶ = 20834978557 is a prime.

Together with 20834978623, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20834978621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20834978623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10417489310 + 10417489311.

It is an arithmetic number, because the mean of its divisors is an integer number (10417489311).

Almost surely, 2^20834978621 is an apocalyptic number.

It is an amenable number.

20834978621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20834978621 is an equidigital number, since it uses as much as digits as its factorization.

20834978621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 50.

The spelling of 20834978621 in words is "twenty billion, eight hundred thirty-four million, nine hundred seventy-eight thousand, six hundred twenty-one".