2001643553 has 32 divisors (see below), whose sum is σ = 2516935680. Its totient is φ = 1549785600.

The previous prime is 2001643549. The next prime is 2001643577. The reversal of 2001643553 is 3553461002.

It is a cyclic number.

It is not a de Polignac number, because 2001643553 - 2² = 2001643549 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2001643753) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 816776 + ... + 819222.

It is an arithmetic number, because the mean of its divisors is an integer number (78654240).

Almost surely, 2^2001643553 is an apocalyptic number.

It is an amenable number.

2001643553 is a deficient number, since it is larger than the sum of its proper divisors (515292127).

2001643553 is a wasteful number, since it uses less digits than its factorization.

2001643553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2657.

The product of its (nonzero) digits is 10800, while the sum is 29.

The square root of 2001643553 is about 44739.7312575746. The cubic root of 2001643553 is about 1260.2660799032.

The spelling of 2001643553 in words is "two billion, one million, six hundred forty-three thousand, five hundred fifty-three".