997890613 has 2 divisors, whose sum is σ = 997890614. Its totient is φ = 997890612.

The previous prime is 997890559. The next prime is 997890623. The reversal of 997890613 is 316098799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 696590449 + 301300164 = 26393^2 + 17358^2 .

It is a cyclic number.

It is not a de Polignac number, because 997890613 - 2²⁵ = 964336181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997890623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498945306 + 498945307.

It is an arithmetic number, because the mean of its divisors is an integer number (498945307).

Almost surely, 2^997890613 is an apocalyptic number.

It is an amenable number.

997890613 is a deficient number, since it is larger than the sum of its proper divisors (1).

997890613 is an equidigital number, since it uses as much as digits as its factorization.

997890613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 734832, while the sum is 52.

The square root of 997890613 is about 31589.4066579289. The cubic root of 997890613 is about 999.2963760294.

It can be divided in two parts, 9978906 and 13, that multiplied together give a triangular number (129725778 = T₁₆₁₀₇).

The spelling of 997890613 in words is "nine hundred ninety-seven million, eight hundred ninety thousand, six hundred thirteen".