20351984975989 has 2 divisors, whose sum is σ = 20351984975990. Its totient is φ = 20351984975988.

The previous prime is 20351984975939. The next prime is 20351984976067. The reversal of 20351984975989 is 98957948915302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19297060836964 + 1054924139025 = 4392842^2 + 1027095^2 .

It is a cyclic number.

It is not a de Polignac number, because 20351984975989 - 2¹¹ = 20351984973941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20351984975929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10175992487994 + 10175992487995.

It is an arithmetic number, because the mean of its divisors is an integer number (10175992487995).

Almost surely, 2^{20351984975989} is an apocalyptic number.

It is an amenable number.

20351984975989 is a deficient number, since it is larger than the sum of its proper divisors (1).

20351984975989 is an equidigital number, since it uses as much as digits as its factorization.

20351984975989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1763596800, while the sum is 79.

The spelling of 20351984975989 in words is "twenty trillion, three hundred fifty-one billion, nine hundred eighty-four million, nine hundred seventy-five thousand, nine hundred eighty-nine".