1980555547391 has 2 divisors, whose sum is σ = 1980555547392. Its totient is φ = 1980555547390.

The previous prime is 1980555547379. The next prime is 1980555547489. The reversal of 1980555547391 is 1937455550891.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1980555547391 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1980555547351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990277773695 + 990277773696.

It is an arithmetic number, because the mean of its divisors is an integer number (990277773696).

Almost surely, 2^{1980555547391} is an apocalyptic number.

1980555547391 is a deficient number, since it is larger than the sum of its proper divisors (1).

1980555547391 is an equidigital number, since it uses as much as digits as its factorization.

1980555547391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020000, while the sum is 62.

The spelling of 1980555547391 in words is "one trillion, nine hundred eighty billion, five hundred fifty-five million, five hundred forty-seven thousand, three hundred ninety-one".