645543071 has 2 divisors, whose sum is σ = 645543072. Its totient is φ = 645543070.

The previous prime is 645543029. The next prime is 645543083. The reversal of 645543071 is 170345546.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-645543071 is a prime.

It is a super-2 number, since 2×645543071² = 833451713032222082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (645549071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322771535 + 322771536.

It is an arithmetic number, because the mean of its divisors is an integer number (322771536).

Almost surely, 2^645543071 is an apocalyptic number.

645543071 is a deficient number, since it is larger than the sum of its proper divisors (1).

645543071 is an equidigital number, since it uses as much as digits as its factorization.

645543071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50400, while the sum is 35.

The square root of 645543071 is about 25407.5396486948. The cubic root of 645543071 is about 864.2546827033.

The spelling of 645543071 in words is "six hundred forty-five million, five hundred forty-three thousand, seventy-one".