21520005123025 has 24 divisors (see below), whose sum is σ = 26864985479544. Its totient is φ = 17099842905600.

The previous prime is 21520005123011. The next prime is 21520005123047. The reversal of 21520005123025 is 52032150002512.

It can be written as a sum of positive squares in 12 ways, for example, as 14365070256384 + 7154934866641 = 3790128^2 + 2674871^2 .

It is not a de Polignac number, because 21520005123025 - 2⁷ = 21520005122897 is a prime.

It is a super-2 number, since 2×21520005123025² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21520005122984 and 21520005123002.

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, 9293355 + ... + 11375695.

It is an arithmetic number, because the mean of its divisors is an integer number (1119374394981).

Almost surely, 2^{21520005123025} is an apocalyptic number.

21520005123025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21520005123025 is a deficient number, since it is larger than the sum of its proper divisors (5344980356519).

21520005123025 is a wasteful number, since it uses less digits than its factorization.

21520005123025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085141 (or 2085136 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 28.

Adding to 21520005123025 its reverse (52032150002512), we get a palindrome (73552155125537).

The spelling of 21520005123025 in words is "twenty-one trillion, five hundred twenty billion, five million, one hundred twenty-three thousand, twenty-five".