1644698427 has 8 divisors (see below), whose sum is σ = 2194678080. Its totient is φ = 1095592200.

The previous prime is 1644698423. The next prime is 1644698437. The reversal of 1644698427 is 7248964461.

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 1644698427 - 2² = 1644698423 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1644698427.

It is not an unprimeable number, because it can be changed into a prime (1644698423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 213949 + ... + 221502.

It is an arithmetic number, because the mean of its divisors is an integer number (274334760).

Almost surely, 2^1644698427 is an apocalyptic number.

1644698427 is a deficient number, since it is larger than the sum of its proper divisors (549979653).

1644698427 is a wasteful number, since it uses less digits than its factorization.

1644698427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436713.

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

The square root of 1644698427 is about 40554.8816666995. The cubic root of 1644698427 is about 1180.3987991794.

The spelling of 1644698427 in words is "one billion, six hundred forty-four million, six hundred ninety-eight thousand, four hundred twenty-seven".