21771730831 has 8 divisors (see below), whose sum is σ = 22525645680. Its totient is φ = 21018027072.

The previous prime is 21771730829. The next prime is 21771730837. The reversal of 21771730831 is 13803717712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21771730831 - 2¹ = 21771730829 is a prime.

It is a super-2 number, since 2×21771730831² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21771730837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 173596 + ... + 271438.

It is an arithmetic number, because the mean of its divisors is an integer number (2815705710).

Almost surely, 2^21771730831 is an apocalyptic number.

21771730831 is a deficient number, since it is larger than the sum of its proper divisors (753914849).

21771730831 is an equidigital number, since it uses as much as digits as its factorization.

21771730831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105545.

The product of its (nonzero) digits is 49392, while the sum is 40.

The spelling of 21771730831 in words is "twenty-one billion, seven hundred seventy-one million, seven hundred thirty thousand, eight hundred thirty-one".