20378687591 has 2 divisors, whose sum is σ = 20378687592. Its totient is φ = 20378687590.

The previous prime is 20378687569. The next prime is 20378687761. The reversal of 20378687591 is 19578687302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20378687591 - 2¹⁴ = 20378671207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20378684591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10189343795 + 10189343796.

It is an arithmetic number, because the mean of its divisors is an integer number (10189343796).

Almost surely, 2^20378687591 is an apocalyptic number.

20378687591 is a deficient number, since it is larger than the sum of its proper divisors (1).

20378687591 is an equidigital number, since it uses as much as digits as its factorization.

20378687591 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5080320, while the sum is 56.

The spelling of 20378687591 in words is "twenty billion, three hundred seventy-eight million, six hundred eighty-seven thousand, five hundred ninety-one".