20843647493 has 2 divisors, whose sum is σ = 20843647494. Its totient is φ = 20843647492.

The previous prime is 20843647483. The next prime is 20843647519. The reversal of 20843647493 is 39474634802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19768922404 + 1074725089 = 140602^2 + 32783^2 .

It is a cyclic number.

It is not a de Polignac number, because 20843647493 - 2¹⁰ = 20843646469 is a prime.

It is a super-4 number, since 4×20843647493⁴ (a number of 42 digits) contains 4444 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20843647483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10421823746 + 10421823747.

It is an arithmetic number, because the mean of its divisors is an integer number (10421823747).

Almost surely, 2^20843647493 is an apocalyptic number.

It is an amenable number.

20843647493 is a deficient number, since it is larger than the sum of its proper divisors (1).

20843647493 is an equidigital number, since it uses as much as digits as its factorization.

20843647493 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3483648, while the sum is 50.

The spelling of 20843647493 in words is "twenty billion, eight hundred forty-three million, six hundred forty-seven thousand, four hundred ninety-three".