1653668644 has 12 divisors (see below), whose sum is σ = 2901681244. Its totient is φ = 824616864.

The previous prime is 1653668617. The next prime is 1653668647. The reversal of 1653668644 is 4468663561.

It can be written as a sum of positive squares in 2 ways, for example, as 919908900 + 733759744 = 30330^2 + 27088^2 .

It is not an unprimeable number, because it can be changed into a prime (1653668647) 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, 552687 + ... + 555670.

Almost surely, 2^1653668644 is an apocalyptic number.

It is an amenable number.

1653668644 is a deficient number, since it is larger than the sum of its proper divisors (1248012600).

1653668644 is a wasteful number, since it uses less digits than its factorization.

1653668644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108734 (or 1108732 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 49.

The square root of 1653668644 is about 40665.3248357861. The cubic root of 1653668644 is about 1182.5408821853.

The spelling of 1653668644 in words is "one billion, six hundred fifty-three million, six hundred sixty-eight thousand, six hundred forty-four".