20840842247 has 2 divisors, whose sum is σ = 20840842248. Its totient is φ = 20840842246.

The previous prime is 20840842193. The next prime is 20840842261. The reversal of 20840842247 is 74224804802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20840842247 - 2²² = 20836647943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20840841247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10420421123 + 10420421124.

It is an arithmetic number, because the mean of its divisors is an integer number (10420421124).

Almost surely, 2^20840842247 is an apocalyptic number.

20840842247 is a deficient number, since it is larger than the sum of its proper divisors (1).

20840842247 is an equidigital number, since it uses as much as digits as its factorization.

20840842247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 229376, while the sum is 41.

The spelling of 20840842247 in words is "twenty billion, eight hundred forty million, eight hundred forty-two thousand, two hundred forty-seven".