20957049977 has 2 divisors, whose sum is σ = 20957049978. Its totient is φ = 20957049976.

The previous prime is 20957049959. The next prime is 20957050003. The reversal of 20957049977 is 77994075902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20956615696 + 434281 = 144764^2 + 659^2 .

It is a cyclic number.

It is not a de Polignac number, because 20957049977 - 2¹⁰ = 20957048953 is a prime.

It is not a weakly prime, because it can be changed into another prime (20957049937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10478524988 + 10478524989.

It is an arithmetic number, because the mean of its divisors is an integer number (10478524989).

Almost surely, 2^20957049977 is an apocalyptic number.

It is an amenable number.

20957049977 is a deficient number, since it is larger than the sum of its proper divisors (1).

20957049977 is an equidigital number, since it uses as much as digits as its factorization.

20957049977 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10001880, while the sum is 59.

The spelling of 20957049977 in words is "twenty billion, nine hundred fifty-seven million, forty-nine thousand, nine hundred seventy-seven".