20847493 has 2 divisors, whose sum is σ = 20847494. Its totient is φ = 20847492.

The previous prime is 20847481. The next prime is 20847523. The reversal of 20847493 is 39474802.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18948609 + 1898884 = 4353^2 + 1378^2 .

It is a cyclic number.

It is not a de Polignac number, because 20847493 - 2²¹ = 18750341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20847403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10423746 + 10423747.

It is an arithmetic number, because the mean of its divisors is an integer number (10423747).

Almost surely, 2^20847493 is an apocalyptic number.

It is an amenable number.

20847493 is a deficient number, since it is larger than the sum of its proper divisors (1).

20847493 is an equidigital number, since it uses as much as digits as its factorization.

20847493 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 20847493 is about 4565.9054961749. The cubic root of 20847493 is about 275.2229288756. Note that the first 3 decimals are identical.

The spelling of 20847493 in words is "twenty million, eight hundred forty-seven thousand, four hundred ninety-three".