21250442125 has 16 divisors (see below), whose sum is σ = 28931512896. Its totient is φ = 15454866000.

The previous prime is 21250442107. The next prime is 21250442173. The reversal of 21250442125 is 52124405212.

It is a happy number.

It is not a de Polignac number, because 21250442125 - 2⁹ = 21250441613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21250442093 and 21250442102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7726059 + ... + 7728808.

It is an arithmetic number, because the mean of its divisors is an integer number (1808219556).

Almost surely, 2^21250442125 is an apocalyptic number.

21250442125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21250442125 is a deficient number, since it is larger than the sum of its proper divisors (7681070771).

21250442125 is a wasteful number, since it uses less digits than its factorization.

21250442125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15454893 (or 15454883 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 28.

Adding to 21250442125 its reverse (52124405212), we get a palindrome (73374847337).

The spelling of 21250442125 in words is "twenty-one billion, two hundred fifty million, four hundred forty-two thousand, one hundred twenty-five".