20981583 has 12 divisors (see below), whose sum is σ = 34636368. Its totient is φ = 11989440.

The previous prime is 20981581. The next prime is 20981593. The reversal of 20981583 is 38518902.

It is not a de Polignac number, because 20981583 - 2¹ = 20981581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981581) 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 11 ways as a sum of consecutive naturals, for example, 166458 + ... + 166583.

It is an arithmetic number, because the mean of its divisors is an integer number (2886364).

Almost surely, 2^20981583 is an apocalyptic number.

20981583 is a deficient number, since it is larger than the sum of its proper divisors (13654785).

20981583 is a wasteful number, since it uses less digits than its factorization.

20981583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333054 (or 333051 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 20981583 is about 4580.5657947463. The cubic root of 20981583 is about 275.8117414991.

The spelling of 20981583 in words is "twenty million, nine hundred eighty-one thousand, five hundred eighty-three".