20125443221 has 4 divisors (see below), whose sum is σ = 21673554252. Its totient is φ = 18577332192.

The previous prime is 20125443197. The next prime is 20125443241. The reversal of 20125443221 is 12234452102.

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 11596920721 + 8528522500 = 107689^2 + 92350^2 .

It is a cyclic number.

It is not a de Polignac number, because 20125443221 - 2⁶ = 20125443157 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 (20125443241) 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, 774055496 + ... + 774055521.

It is an arithmetic number, because the mean of its divisors is an integer number (5418388563).

Almost surely, 2^20125443221 is an apocalyptic number.

It is an amenable number.

20125443221 is a deficient number, since it is larger than the sum of its proper divisors (1548111031).

20125443221 is a wasteful number, since it uses less digits than its factorization.

20125443221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1548111030.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 20125443221 its reverse (12234452102), we get a palindrome (32359895323).

The spelling of 20125443221 in words is "twenty billion, one hundred twenty-five million, four hundred forty-three thousand, two hundred twenty-one".