20975871 has 24 divisors (see below), whose sum is σ = 33590784. Its totient is φ = 11597040.

The previous prime is 20975869. The next prime is 20975879. The reversal of 20975871 is 17857902.

It is not a de Polignac number, because 20975871 - 2¹ = 20975869 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20975879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2256 + ... + 6858.

It is an arithmetic number, because the mean of its divisors is an integer number (1399616).

Almost surely, 2^20975871 is an apocalyptic number.

20975871 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20975871 is a deficient number, since it is larger than the sum of its proper divisors (12614913).

20975871 is a wasteful number, since it uses less digits than its factorization.

20975871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4651 (or 4644 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 20975871 is about 4579.9422485442. The cubic root of 20975871 is about 275.7867103459.

The spelling of 20975871 in words is "twenty million, nine hundred seventy-five thousand, eight hundred seventy-one".