20858465581 has 8 divisors (see below), whose sum is σ = 21447237240. Its totient is φ = 20271011328.

The previous prime is 20858465567. The next prime is 20858465587. The reversal of 20858465581 is 18556485802.

It can be written as a sum of positive squares in 4 ways, for example, as 4547344356 + 16311121225 = 67434^2 + 127715^2 .

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 20858465581 - 2⁵ = 20858465549 is a prime.

It is a super-2 number, since 2×20858465581² (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 (20858465587) 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, 297196 + ... + 360613.

It is an arithmetic number, because the mean of its divisors is an integer number (2680904655).

Almost surely, 2^20858465581 is an apocalyptic number.

It is an amenable number.

20858465581 is a deficient number, since it is larger than the sum of its proper divisors (588771659).

20858465581 is an equidigital number, since it uses as much as digits as its factorization.

20858465581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658703.

The product of its (nonzero) digits is 3072000, while the sum is 52.

The spelling of 20858465581 in words is "twenty billion, eight hundred fifty-eight million, four hundred sixty-five thousand, five hundred eighty-one".