645454849 has 4 divisors (see below), whose sum is σ = 695105236. Its totient is φ = 595804464.

The previous prime is 645454837. The next prime is 645454879. The reversal of 645454849 is 948454546.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 85895824 + 559559025 = 9268^2 + 23655^2 .

It is a cyclic number.

It is not a de Polignac number, because 645454849 - 2⁷ = 645454721 is a prime.

It is a super-2 number, since 2×645454849² = 833223924195225602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (645454879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24825174 + ... + 24825199.

It is an arithmetic number, because the mean of its divisors is an integer number (173776309).

Almost surely, 2^645454849 is an apocalyptic number.

It is an amenable number.

645454849 is a deficient number, since it is larger than the sum of its proper divisors (49650387).

645454849 is a wasteful number, since it uses less digits than its factorization.

645454849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49650386.

The product of its digits is 2764800, while the sum is 49.

The square root of 645454849 is about 25405.8034511802. The cubic root of 645454849 is about 864.2153102980.

The spelling of 645454849 in words is "six hundred forty-five million, four hundred fifty-four thousand, eight hundred forty-nine".