617971813 has 2 divisors, whose sum is σ = 617971814. Its totient is φ = 617971812.

The previous prime is 617971807. The next prime is 617971909. The reversal of 617971813 is 318179716.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 603095364 + 14876449 = 24558^2 + 3857^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-617971813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 617971813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (617978813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308985906 + 308985907.

It is an arithmetic number, because the mean of its divisors is an integer number (308985907).

Almost surely, 2^617971813 is an apocalyptic number.

It is an amenable number.

617971813 is a deficient number, since it is larger than the sum of its proper divisors (1).

617971813 is an equidigital number, since it uses as much as digits as its factorization.

617971813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 43.

The square root of 617971813 is about 24859.0388591353. The cubic root of 617971813 is about 851.7710767368.

The spelling of 617971813 in words is "six hundred seventeen million, nine hundred seventy-one thousand, eight hundred thirteen".