20890644293 has 4 divisors (see below), whose sum is σ = 22119505740. Its totient is φ = 19661782848.

The previous prime is 20890644289. The next prime is 20890644301. The reversal of 20890644293 is 39244609802.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9701659009 + 11188985284 = 98497^2 + 105778^2 .

It is a cyclic number.

It is not a de Polignac number, because 20890644293 - 2² = 20890644289 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 (20890644253) 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, 614430698 + ... + 614430731.

It is an arithmetic number, because the mean of its divisors is an integer number (5529876435).

Almost surely, 2^20890644293 is an apocalyptic number.

It is an amenable number.

20890644293 is a deficient number, since it is larger than the sum of its proper divisors (1228861447).

20890644293 is a wasteful number, since it uses less digits than its factorization.

20890644293 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1228861446.

The product of its (nonzero) digits is 746496, while the sum is 47.

The spelling of 20890644293 in words is "twenty billion, eight hundred ninety million, six hundred forty-four thousand, two hundred ninety-three".