21221145125 has 64 divisors (see below), whose sum is σ = 29317766400. Its totient is φ = 15271200000.

The previous prime is 21221145091. The next prime is 21221145133. The reversal of 21221145125 is 52154112212.

It is a happy number.

It is not a de Polignac number, because 21221145125 - 2⁶ = 21221145061 is a prime.

It is a super-2 number, since 2×21221145125² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21221145094 and 21221145103.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 4198850 + ... + 4203900.

It is an arithmetic number, because the mean of its divisors is an integer number (458090100).

Almost surely, 2^21221145125 is an apocalyptic number.

21221145125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21221145125 is a deficient number, since it is larger than the sum of its proper divisors (8096621275).

21221145125 is a wasteful number, since it uses less digits than its factorization.

21221145125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5175 (or 5165 counting only the distinct ones).

The product of its digits is 1600, while the sum is 26.

Adding to 21221145125 its reverse (52154112212), we get a palindrome (73375257337).

The spelling of 21221145125 in words is "twenty-one billion, two hundred twenty-one million, one hundred forty-five thousand, one hundred twenty-five".