1643240653 has 8 divisors (see below), whose sum is σ = 1706660096. Its totient is φ = 1580472000.

The previous prime is 1643240639. The next prime is 1643240713. The reversal of 1643240653 is 3560423461.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643240653 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 (1643240603) 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, 157548 + ... + 167653.

It is an arithmetic number, because the mean of its divisors is an integer number (213332512).

Almost surely, 2^1643240653 is an apocalyptic number.

It is an amenable number.

1643240653 is a deficient number, since it is larger than the sum of its proper divisors (63419443).

1643240653 is a wasteful number, since it uses less digits than its factorization.

1643240653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325395.

The product of its (nonzero) digits is 51840, while the sum is 34.

The square root of 1643240653 is about 40536.9048275766. The cubic root of 1643240653 is about 1180.0499483310.

The spelling of 1643240653 in words is "one billion, six hundred forty-three million, two hundred forty thousand, six hundred fifty-three".