20905554877 has 2 divisors, whose sum is σ = 20905554878. Its totient is φ = 20905554876.

The previous prime is 20905554863. The next prime is 20905554893. The reversal of 20905554877 is 77845550902.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13878253636 + 7027301241 = 117806^2 + 83829^2 .

It is a cyclic number.

It is not a de Polignac number, because 20905554877 - 2¹⁵ = 20905522109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20905554277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10452777438 + 10452777439.

It is an arithmetic number, because the mean of its divisors is an integer number (10452777439).

Almost surely, 2^20905554877 is an apocalyptic number.

It is an amenable number.

20905554877 is a deficient number, since it is larger than the sum of its proper divisors (1).

20905554877 is an equidigital number, since it uses as much as digits as its factorization.

20905554877 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3528000, while the sum is 52.

The spelling of 20905554877 in words is "twenty billion, nine hundred five million, five hundred fifty-four thousand, eight hundred seventy-seven".