1644071357 has 4 divisors (see below), whose sum is σ = 1688505756. Its totient is φ = 1599636960.

The previous prime is 1644071339. The next prime is 1644071437. The reversal of 1644071357 is 7531704461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7531704461 = 6473 ⋅1163557.

It can be written as a sum of positive squares in 2 ways, for example, as 1516245721 + 127825636 = 38939^2 + 11306^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1644071357 is a prime.

It is a super-3 number, since 3×1644071357³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1644071357.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644071657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22217144 + ... + 22217217.

It is an arithmetic number, because the mean of its divisors is an integer number (422126439).

Almost surely, 2^1644071357 is an apocalyptic number.

It is an amenable number.

1644071357 is a deficient number, since it is larger than the sum of its proper divisors (44434399).

1644071357 is an equidigital number, since it uses as much as digits as its factorization.

1644071357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44434398.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 1644071357 is about 40547.1498011882. The cubic root of 1644071357 is about 1180.2487642240.

The spelling of 1644071357 in words is "one billion, six hundred forty-four million, seventy-one thousand, three hundred fifty-seven".