997543510421 has 2 divisors, whose sum is σ = 997543510422. Its totient is φ = 997543510420.

The previous prime is 997543510343. The next prime is 997543510433. The reversal of 997543510421 is 124015345799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 936849768100 + 60693742321 = 967910^2 + 246361^2 .

It is a cyclic number.

It is not a de Polignac number, because 997543510421 - 2¹⁸ = 997543248277 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 997543510421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997543510321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498771755210 + 498771755211.

It is an arithmetic number, because the mean of its divisors is an integer number (498771755211).

Almost surely, 2^997543510421 is an apocalyptic number.

It is an amenable number.

997543510421 is a deficient number, since it is larger than the sum of its proper divisors (1).

997543510421 is an equidigital number, since it uses as much as digits as its factorization.

997543510421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1360800, while the sum is 50.

The spelling of 997543510421 in words is "nine hundred ninety-seven billion, five hundred forty-three million, five hundred ten thousand, four hundred twenty-one".