21125334145 has 16 divisors (see below), whose sum is σ = 25870482000. Its totient is φ = 16557032448.

The previous prime is 21125334127. The next prime is 21125334157. The reversal of 21125334145 is 54143352112.

It can be written as a sum of positive squares in 8 ways, for example, as 93373569 + 21031960576 = 9663^2 + 145024^2 .

It is a cyclic number.

It is not a de Polignac number, because 21125334145 - 2⁹ = 21125333633 is a prime.

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, 169260 + ... + 266269.

It is an arithmetic number, because the mean of its divisors is an integer number (1616905125).

Almost surely, 2^21125334145 is an apocalyptic number.

It is an amenable number.

21125334145 is a deficient number, since it is larger than the sum of its proper divisors (4745147855).

21125334145 is a wasteful number, since it uses less digits than its factorization.

21125334145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435732.

The product of its digits is 14400, while the sum is 31.

Adding to 21125334145 its reverse (54143352112), we get a palindrome (75268686257).

The spelling of 21125334145 in words is "twenty-one billion, one hundred twenty-five million, three hundred thirty-four thousand, one hundred forty-five".