20974942687 has 2 divisors, whose sum is σ = 20974942688. Its totient is φ = 20974942686.

The previous prime is 20974942673. The next prime is 20974942711. The reversal of 20974942687 is 78624947902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20974942687 - 2¹¹ = 20974940639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20974942187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10487471343 + 10487471344.

It is an arithmetic number, because the mean of its divisors is an integer number (10487471344).

Almost surely, 2^20974942687 is an apocalyptic number.

20974942687 is a deficient number, since it is larger than the sum of its proper divisors (1).

20974942687 is an equidigital number, since it uses as much as digits as its factorization.

20974942687 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12192768, while the sum is 58.

The spelling of 20974942687 in words is "twenty billion, nine hundred seventy-four million, nine hundred forty-two thousand, six hundred eighty-seven".