1644749139 has 8 divisors (see below), whose sum is σ = 2392362432. Its totient is φ = 996817640.

The previous prime is 1644749101. The next prime is 1644749143. The reversal of 1644749139 is 9319474461.

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

It is a cyclic number.

It is not a de Polignac number, because 1644749139 - 2⁹ = 1644748627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1644749149) 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, 24920409 + ... + 24920474.

It is an arithmetic number, because the mean of its divisors is an integer number (299045304).

Almost surely, 2^1644749139 is an apocalyptic number.

1644749139 is a deficient number, since it is larger than the sum of its proper divisors (747613293).

1644749139 is a wasteful number, since it uses less digits than its factorization.

1644749139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49840897.

The product of its digits is 653184, while the sum is 48.

The square root of 1644749139 is about 40555.5068887075. The cubic root of 1644749139 is about 1180.4109310425.

The spelling of 1644749139 in words is "one billion, six hundred forty-four million, seven hundred forty-nine thousand, one hundred thirty-nine".