20985479 has 2 divisors, whose sum is σ = 20985480. Its totient is φ = 20985478.

The previous prime is 20985467. The next prime is 20985487. The reversal of 20985479 is 97458902.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20985479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20985409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10492739 + 10492740.

It is an arithmetic number, because the mean of its divisors is an integer number (10492740).

Almost surely, 2^20985479 is an apocalyptic number.

20985479 is a deficient number, since it is larger than the sum of its proper divisors (1).

20985479 is an equidigital number, since it uses as much as digits as its factorization.

20985479 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 181440, while the sum is 44.

The square root of 20985479 is about 4580.9910499803. The cubic root of 20985479 is about 275.8288119626.

The spelling of 20985479 in words is "twenty million, nine hundred eighty-five thousand, four hundred seventy-nine".