645220155 has 16 divisors (see below), whose sum is σ = 1033173504. Its totient is φ = 343843680.

The previous prime is 645220151. The next prime is 645220181. The reversal of 645220155 is 551022546.

It is not a de Polignac number, because 645220155 - 2² = 645220151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (645220151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3150 + ... + 36060.

It is an arithmetic number, because the mean of its divisors is an integer number (64573344).

Almost surely, 2^645220155 is an apocalyptic number.

645220155 is a deficient number, since it is larger than the sum of its proper divisors (387953349).

645220155 is a wasteful number, since it uses less digits than its factorization.

645220155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34226.

The product of its (nonzero) digits is 12000, while the sum is 30.

The square root of 645220155 is about 25401.1841259418. The cubic root of 645220155 is about 864.1105517511.

The spelling of 645220155 in words is "six hundred forty-five million, two hundred twenty thousand, one hundred fifty-five".