20211847581 has 8 divisors (see below), whose sum is σ = 27575854240. Its totient is φ = 13161202992.

The previous prime is 20211847541. The next prime is 20211847583. The reversal of 20211847581 is 18574811202.

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

It is not a de Polignac number, because 20211847581 - 2¹⁴ = 20211831197 is a prime.

It is a super-2 number, since 2×20211847581² (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 (20211847583) 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 7 ways as a sum of consecutive naturals, for example, 78340366 + ... + 78340623.

It is an arithmetic number, because the mean of its divisors is an integer number (3446981780).

Almost surely, 2^20211847581 is an apocalyptic number.

It is an amenable number.

20211847581 is a deficient number, since it is larger than the sum of its proper divisors (7364006659).

20211847581 is a wasteful number, since it uses less digits than its factorization.

20211847581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156681035.

The product of its (nonzero) digits is 35840, while the sum is 39.

The spelling of 20211847581 in words is "twenty billion, two hundred eleven million, eight hundred forty-seven thousand, five hundred eighty-one".