645220855 has 8 divisors (see below), whose sum is σ = 800964000. Its totient is φ = 498377376.

The previous prime is 645220819. The next prime is 645220861. The reversal of 645220855 is 558022546.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 645220855 - 2⁷ = 645220727 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2224755 + ... + 2225044.

It is an arithmetic number, because the mean of its divisors is an integer number (100120500).

Almost surely, 2^645220855 is an apocalyptic number.

645220855 is a deficient number, since it is larger than the sum of its proper divisors (155743145).

645220855 is a wasteful number, since it uses less digits than its factorization.

645220855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4449833.

The product of its (nonzero) digits is 96000, while the sum is 37.

The square root of 645220855 is about 25401.1979048233. The cubic root of 645220855 is about 864.1108642425.

The spelling of 645220855 in words is "six hundred forty-five million, two hundred twenty thousand, eight hundred fifty-five".