20905143 has 16 divisors (see below), whose sum is σ = 32954880. Its totient is φ = 11533536.

The previous prime is 20905133. The next prime is 20905153. The reversal of 20905143 is 34150902.

It is an interprime number because it is at equal distance from previous prime (20905133) and next prime (20905153).

It is not a de Polignac number, because 20905143 - 2¹⁰ = 20904119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20905103) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16555 + ... + 17772.

It is an arithmetic number, because the mean of its divisors is an integer number (2059680).

Almost surely, 2^20905143 is an apocalyptic number.

20905143 is a deficient number, since it is larger than the sum of its proper divisors (12049737).

20905143 is a wasteful number, since it uses less digits than its factorization.

20905143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34366.

The product of its (nonzero) digits is 1080, while the sum is 24.

The square root of 20905143 is about 4572.2142338259. The cubic root of 20905143 is about 275.4763885900.

The spelling of 20905143 in words is "twenty million, nine hundred five thousand, one hundred forty-three".