1644126842 has 4 divisors (see below), whose sum is σ = 2466190266. Its totient is φ = 822063420.

The previous prime is 1644126793. The next prime is 1644126851. The reversal of 1644126842 is 2486214461.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 1618533361 + 25593481 = 40231^2 + 5059^2 .

It is a super-3 number, since 3×1644126842³ (a number of 29 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1644126796 and 1644126805.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 411031709 + ... + 411031712.

Almost surely, 2^1644126842 is an apocalyptic number.

1644126842 is a deficient number, since it is larger than the sum of its proper divisors (822063424).

1644126842 is an equidigital number, since it uses as much as digits as its factorization.

1644126842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822063423.

The product of its digits is 73728, while the sum is 38.

The square root of 1644126842 is about 40547.8339988710. The cubic root of 1644126842 is about 1180.2620412970.

The spelling of 1644126842 in words is "one billion, six hundred forty-four million, one hundred twenty-six thousand, eight hundred forty-two".