1644268947 has 8 divisors (see below), whose sum is σ = 2208131520. Its totient is φ = 1088292840.

The previous prime is 1644268943. The next prime is 1644268957. The reversal of 1644268947 is 7498624461.

It is a happy number.

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

It is not a de Polignac number, because 1644268947 - 2² = 1644268943 is a prime.

It is a super-3 number, since 3×1644268947³ (a number of 29 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1644268947.

It is not an unprimeable number, because it can be changed into a prime (1644268943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1971129 + ... + 1971962.

It is an arithmetic number, because the mean of its divisors is an integer number (276016440).

Almost surely, 2^1644268947 is an apocalyptic number.

1644268947 is a deficient number, since it is larger than the sum of its proper divisors (563862573).

1644268947 is a wasteful number, since it uses less digits than its factorization.

1644268947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3943233.

The product of its digits is 2322432, while the sum is 51.

The square root of 1644268947 is about 40549.5862740916. The cubic root of 1644268947 is about 1180.2960444126.

The spelling of 1644268947 in words is "one billion, six hundred forty-four million, two hundred sixty-eight thousand, nine hundred forty-seven".