645900271 has 4 divisors (see below), whose sum is σ = 645975792. Its totient is φ = 645824752.

The previous prime is 645900263. The next prime is 645900361. The reversal of 645900271 is 172009546.

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

It is a cyclic number.

It is not a de Polignac number, because 645900271 - 2³ = 645900263 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 (645900371) 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, 23011 + ... + 42676.

It is an arithmetic number, because the mean of its divisors is an integer number (161493948).

Almost surely, 2^645900271 is an apocalyptic number.

645900271 is a deficient number, since it is larger than the sum of its proper divisors (75521).

645900271 is an equidigital number, since it uses as much as digits as its factorization.

645900271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75520.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 645900271 is about 25414.5680860407. The cubic root of 645900271 is about 864.4140600627.

The spelling of 645900271 in words is "six hundred forty-five million, nine hundred thousand, two hundred seventy-one".