1644222655 has 12 divisors (see below), whose sum is σ = 1998396792. Its totient is φ = 1298703120.

The previous prime is 1644222647. The next prime is 1644222661. The reversal of 1644222655 is 5562224461.

It is a happy number.

It is not a de Polignac number, because 1644222655 - 2³ = 1644222647 is a prime.

It is a super-3 number, since 3×1644222655³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4860 + ... + 57550.

It is an arithmetic number, because the mean of its divisors is an integer number (166533066).

Almost surely, 2^1644222655 is an apocalyptic number.

1644222655 is a deficient number, since it is larger than the sum of its proper divisors (354174137).

1644222655 is an frugal number, since it uses more digits than its factorization.

1644222655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52854 (or 52775 counting only the distinct ones).

The product of its digits is 115200, while the sum is 37.

The square root of 1644222655 is about 40549.0154627705. The cubic root of 1644222655 is about 1180.2849678027.

The spelling of 1644222655 in words is "one billion, six hundred forty-four million, two hundred twenty-two thousand, six hundred fifty-five".