20731284 has 36 divisors (see below), whose sum is σ = 59891104. Its totient is φ = 5923152.

The previous prime is 20731283. The next prime is 20731301. The reversal of 20731284 is 48213702.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×20731284² = 859572272577312, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731283) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40882 + ... + 41385.

Almost surely, 2^20731284 is an apocalyptic number.

It is an amenable number.

20731284 is an abundant number, since it is smaller than the sum of its proper divisors (39159820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20731284 is a wasteful number, since it uses less digits than its factorization.

20731284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82284 (or 82279 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 20731284 is about 4553.1619782301. The cubic root of 20731284 is about 274.7105891940.

Adding to 20731284 its reverse (48213702), we get a palindrome (68944986).

The spelling of 20731284 in words is "twenty million, seven hundred thirty-one thousand, two hundred eighty-four".