516601991 has 2 divisors, whose sum is σ = 516601992. Its totient is φ = 516601990.

The previous prime is 516601951. The next prime is 516601993. The reversal of 516601991 is 199106615.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 516601991 - 2¹⁰ = 516600967 is a prime.

Together with 516601993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (516601993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 258300995 + 258300996.

It is an arithmetic number, because the mean of its divisors is an integer number (258300996).

Almost surely, 2^516601991 is an apocalyptic number.

516601991 is a deficient number, since it is larger than the sum of its proper divisors (1).

516601991 is an equidigital number, since it uses as much as digits as its factorization.

516601991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14580, while the sum is 38.

The square root of 516601991 is about 22728.8801087955. The cubic root of 516601991 is about 802.3897247243.

The spelling of 516601991 in words is "five hundred sixteen million, six hundred one thousand, nine hundred ninety-one".