645210801 has 9 divisors (see below), whose sum is σ = 932081241. Its totient is φ = 430089732.

The previous prime is 645210793. The next prime is 645210803. The reversal of 645210801 is 108012546.

The square root of 645210801 is 25401.

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

645210801 is a `hidden beast` number, since 64 + 521 + 0 + 80 + 1 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 645210801 - 2³ = 645210793 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645210803) 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, 71970 + ... + 80436.

Almost surely, 2^645210801 is an apocalyptic number.

645210801 is the 25401-st square number.

645210801 is the 12701-st centered octagonal number.

It is an amenable number.

645210801 is a deficient number, since it is larger than the sum of its proper divisors (286870440).

645210801 is an frugal number, since it uses more digits than its factorization.

645210801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16940 (or 8470 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The cubic root of 645210801 is about 864.1063759521.

The spelling of 645210801 in words is "six hundred forty-five million, two hundred ten thousand, eight hundred one".