21121143525 has 24 divisors (see below), whose sum is σ = 38800324160. Its totient is φ = 11264609520.

The previous prime is 21121143517. The next prime is 21121143557. The reversal of 21121143525 is 52534112112.

It is a happy number.

21121143525 is a `hidden beast` number, since 2 + 1 + 121 + 14 + 3 + 525 = 666.

It is not a de Polignac number, because 21121143525 - 2³ = 21121143517 is a prime.

It is a super-2 number, since 2×21121143525² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15644617 + ... + 15645966.

Almost surely, 2^21121143525 is an apocalyptic number.

21121143525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21121143525 is a deficient number, since it is larger than the sum of its proper divisors (17679180635).

21121143525 is a wasteful number, since it uses less digits than its factorization.

21121143525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31290602 (or 31290591 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

Adding to 21121143525 its reverse (52534112112), we get a palindrome (73655255637).

The spelling of 21121143525 in words is "twenty-one billion, one hundred twenty-one million, one hundred forty-three thousand, five hundred twenty-five".