20840177639 has 2 divisors, whose sum is σ = 20840177640. Its totient is φ = 20840177638.

The previous prime is 20840177627. The next prime is 20840177641. The reversal of 20840177639 is 93677104802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20840177639 - 2⁸ = 20840177383 is a prime.

It is a super-2 number, since 2×20840177639² (a number of 21 digits) contains 22 as substring.

Together with 20840177641, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20840177593 and 20840177602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20840177669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10420088819 + 10420088820.

It is an arithmetic number, because the mean of its divisors is an integer number (10420088820).

Almost surely, 2^20840177639 is an apocalyptic number.

20840177639 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840177639 is an equidigital number, since it uses as much as digits as its factorization.

20840177639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 508032, while the sum is 47.

The spelling of 20840177639 in words is "twenty billion, eight hundred forty million, one hundred seventy-seven thousand, six hundred thirty-nine".