664221155 has 16 divisors (see below), whose sum is σ = 876645504. Its totient is φ = 480063360.

The previous prime is 664221143. The next prime is 664221167. The reversal of 664221155 is 551122466.

It is an interprime number because it is at equal distance from previous prime (664221143) and next prime (664221167).

It is not a de Polignac number, because 664221155 - 2¹⁸ = 663959011 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105656 + ... + 111765.

It is an arithmetic number, because the mean of its divisors is an integer number (54790344).

Almost surely, 2^664221155 is an apocalyptic number.

664221155 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

664221155 is a deficient number, since it is larger than the sum of its proper divisors (212424349).

664221155 is a wasteful number, since it uses less digits than its factorization.

664221155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217486.

The product of its digits is 14400, while the sum is 32.

The square root of 664221155 is about 25772.4883354324. The cubic root of 664221155 is about 872.5109803409.

The spelling of 664221155 in words is "six hundred sixty-four million, two hundred twenty-one thousand, one hundred fifty-five".