645150773 has 4 divisors (see below), whose sum is σ = 645711468. Its totient is φ = 644590080.

The previous prime is 645150767. The next prime is 645150809. The reversal of 645150773 is 377051546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 377051546 = 2 ⋅188525773.

It can be written as a sum of positive squares in 2 ways, for example, as 584575684 + 60575089 = 24178^2 + 7783^2 .

It is a cyclic number.

It is not a de Polignac number, because 645150773 - 2¹⁰ = 645149749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645150743) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 278618 + ... + 280923.

It is an arithmetic number, because the mean of its divisors is an integer number (161427867).

Almost surely, 2^645150773 is an apocalyptic number.

It is an amenable number.

645150773 is a deficient number, since it is larger than the sum of its proper divisors (560695).

645150773 is a wasteful number, since it uses less digits than its factorization.

645150773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 560694.

The product of its (nonzero) digits is 88200, while the sum is 38.

The square root of 645150773 is about 25399.8183654923. The cubic root of 645150773 is about 864.0795773791.

The spelling of 645150773 in words is "six hundred forty-five million, one hundred fifty thousand, seven hundred seventy-three".