20584981 has 4 divisors (see below), whose sum is σ = 20777472. Its totient is φ = 20392492.

The previous prime is 20584979. The next prime is 20584997. The reversal of 20584981 is 18948502.

20584981 = T₃₇₀₃ + T₃₇₀₄ + T₃₇₀₅.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20584981 - 2¹ = 20584979 is a prime.

It is a super-2 number, since 2×20584981² = 847482885540722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20584981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20587981) 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 3 ways as a sum of consecutive naturals, for example, 96085 + ... + 96298.

It is an arithmetic number, because the mean of its divisors is an integer number (5194368).

Almost surely, 2^20584981 is an apocalyptic number.

20584981 is the 3705-th centered triangular number.

It is an amenable number.

20584981 is a deficient number, since it is larger than the sum of its proper divisors (192491).

20584981 is a wasteful number, since it uses less digits than its factorization.

20584981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192490.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 20584981 is about 4537.0674449472. The cubic root of 20584981 is about 274.0628418917.

The spelling of 20584981 in words is "twenty million, five hundred eighty-four thousand, nine hundred eighty-one".