645109201 has 9 divisors (see below), whose sum is σ = 709394203. Its totient is φ = 586208920.

The previous prime is 645109121. The next prime is 645109207. The reversal of 645109201 is 102901546.

The square root of 645109201 is 25399.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 538193601 + 106915600 = 23199^2 + 10340^2 .

It is not a de Polignac number, because 645109201 - 2¹¹ = 645107153 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645109201.

It is not an unprimeable number, because it can be changed into a prime (645109207) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 278235 + ... + 280543.

Almost surely, 2^645109201 is an apocalyptic number.

645109201 is the 25399-th square number.

645109201 is the 12700-th centered octagonal number.

It is an amenable number.

645109201 is a deficient number, since it is larger than the sum of its proper divisors (64285002).

645109201 is an frugal number, since it uses more digits than its factorization.

645109201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4640 (or 2320 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The cubic root of 645109201 is about 864.0610172278.

The spelling of 645109201 in words is "six hundred forty-five million, one hundred nine thousand, two hundred one".