997043554781 has 2 divisors, whose sum is σ = 997043554782. Its totient is φ = 997043554780.

The previous prime is 997043554769. The next prime is 997043554831. The reversal of 997043554781 is 187455340799.

997043554781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 928158828100 + 68884726681 = 963410^2 + 262459^2 .

It is an emirp because it is prime and its reverse (187455340799) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-997043554781 is a prime.

It is a super-2 number, since 2×997043554781² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997043554711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498521777390 + 498521777391.

It is an arithmetic number, because the mean of its divisors is an integer number (498521777391).

Almost surely, 2^997043554781 is an apocalyptic number.

It is an amenable number.

997043554781 is a deficient number, since it is larger than the sum of its proper divisors (1).

997043554781 is an equidigital number, since it uses as much as digits as its factorization.

997043554781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38102400, while the sum is 62.

The spelling of 997043554781 in words is "nine hundred ninety-seven billion, forty-three million, five hundred fifty-four thousand, seven hundred eighty-one".