20602985017991 has 2 divisors, whose sum is σ = 20602985017992. Its totient is φ = 20602985017990.

The previous prime is 20602985017889. The next prime is 20602985017997. The reversal of 20602985017991 is 19971058920602.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20602985017991 - 2³⁴ = 20585805148807 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20602985017991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20602985017997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10301492508995 + 10301492508996.

It is an arithmetic number, because the mean of its divisors is an integer number (10301492508996).

Almost surely, 2^{20602985017991} is an apocalyptic number.

20602985017991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20602985017991 is an equidigital number, since it uses as much as digits as its factorization.

20602985017991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4898880, while the sum is 59.

The spelling of 20602985017991 in words is "twenty trillion, six hundred two billion, nine hundred eighty-five million, seventeen thousand, nine hundred ninety-one".