20835091643 has 4 divisors (see below), whose sum is σ = 20853163128. Its totient is φ = 20817020160.

The previous prime is 20835091637. The next prime is 20835091663. The reversal of 20835091643 is 34619053802.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20835091643 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20835091643.

It is not an unprimeable number, because it can be changed into a prime (20835091603) 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, 9034013 + ... + 9036318.

It is an arithmetic number, because the mean of its divisors is an integer number (5213290782).

Almost surely, 2^20835091643 is an apocalyptic number.

20835091643 is a deficient number, since it is larger than the sum of its proper divisors (18071485).

20835091643 is a wasteful number, since it uses less digits than its factorization.

20835091643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18071484.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 20835091643 in words is "twenty billion, eight hundred thirty-five million, ninety-one thousand, six hundred forty-three".