20849949457 has 2 divisors, whose sum is σ = 20849949458. Its totient is φ = 20849949456.

The previous prime is 20849949427. The next prime is 20849949481. The reversal of 20849949457 is 75494994802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13491054801 + 7358894656 = 116151^2 + 85784^2 .

It is a cyclic number.

It is not a de Polignac number, because 20849949457 - 2³¹ = 18702465809 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20849949395 and 20849949404.

It is not a weakly prime, because it can be changed into another prime (20849949427) 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 as a sum of consecutive naturals, namely, 10424974728 + 10424974729.

It is an arithmetic number, because the mean of its divisors is an integer number (10424974729).

Almost surely, 2^20849949457 is an apocalyptic number.

It is an amenable number.

20849949457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20849949457 is an equidigital number, since it uses as much as digits as its factorization.

20849949457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26127360, while the sum is 61.

The spelling of 20849949457 in words is "twenty billion, eight hundred forty-nine million, nine hundred forty-nine thousand, four hundred fifty-seven".