1644646053 has 4 divisors (see below), whose sum is σ = 2192861408. Its totient is φ = 1096430700.

The previous prime is 1644646049. The next prime is 1644646067. The reversal of 1644646053 is 3506464461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3506464461 = 3 ⋅1168821487.

It is not a de Polignac number, because 1644646053 - 2² = 1644646049 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644646013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274107673 + ... + 274107678.

It is an arithmetic number, because the mean of its divisors is an integer number (548215352).

Almost surely, 2^1644646053 is an apocalyptic number.

It is an amenable number.

1644646053 is a deficient number, since it is larger than the sum of its proper divisors (548215355).

1644646053 is an equidigital number, since it uses as much as digits as its factorization.

1644646053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 548215354.

The product of its (nonzero) digits is 207360, while the sum is 39.

The square root of 1644646053 is about 40554.2359439800. The cubic root of 1644646053 is about 1180.3862694532.

The spelling of 1644646053 in words is "one billion, six hundred forty-four million, six hundred forty-six thousand, fifty-three".