20858858221 has 4 divisors (see below), whose sum is σ = 20859207292. Its totient is φ = 20858509152.

The previous prime is 20858858201. The next prime is 20858858243. The reversal of 20858858221 is 12285885802.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20718435721 + 140422500 = 143939^2 + 11850^2 .

It is a cyclic number.

It is not a de Polignac number, because 20858858221 - 2²⁵ = 20825303789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20858858201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59730 + ... + 212803.

It is an arithmetic number, because the mean of its divisors is an integer number (5214801823).

Almost surely, 2^20858858221 is an apocalyptic number.

It is an amenable number.

20858858221 is a deficient number, since it is larger than the sum of its proper divisors (349071).

20858858221 is an equidigital number, since it uses as much as digits as its factorization.

20858858221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 349070.

The product of its (nonzero) digits is 819200, while the sum is 49.

The spelling of 20858858221 in words is "twenty billion, eight hundred fifty-eight million, eight hundred fifty-eight thousand, two hundred twenty-one".