20781732331 has 4 divisors (see below), whose sum is σ = 22004187192. Its totient is φ = 19559277472.

The previous prime is 20781732287. The next prime is 20781732341. The reversal of 20781732331 is 13323718702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20781732331 - 2⁷ = 20781732203 is a prime.

It is a super-2 number, since 2×20781732331² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20781732341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 611227405 + ... + 611227438.

It is an arithmetic number, because the mean of its divisors is an integer number (5501046798).

Almost surely, 2^20781732331 is an apocalyptic number.

20781732331 is a deficient number, since it is larger than the sum of its proper divisors (1222454861).

20781732331 is a wasteful number, since it uses less digits than its factorization.

20781732331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1222454860.

The product of its (nonzero) digits is 42336, while the sum is 37.

The spelling of 20781732331 in words is "twenty billion, seven hundred eighty-one million, seven hundred thirty-two thousand, three hundred thirty-one".