21513504155225 has 48 divisors (see below), whose sum is σ = 28431662007168. Its totient is φ = 16092023639040.

The previous prime is 21513504155177. The next prime is 21513504155237. The reversal of 21513504155225 is 52255140531512.

It is not a de Polignac number, because 21513504155225 - 2⁶ = 21513504155161 is a prime.

It is a super-2 number, since 2×21513504155225² (a number of 27 digits) contains 22 as substring.

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 47 ways as a sum of consecutive naturals, for example, 122912222 + ... + 123087128.

It is an arithmetic number, because the mean of its divisors is an integer number (592326291816).

Almost surely, 2^{21513504155225} is an apocalyptic number.

21513504155225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21513504155225 is a deficient number, since it is larger than the sum of its proper divisors (6918157851943).

21513504155225 is a wasteful number, since it uses less digits than its factorization.

21513504155225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176834 (or 176829 counting only the distinct ones).

The product of its (nonzero) digits is 300000, while the sum is 41.

Adding to 21513504155225 its reverse (52255140531512), we get a palindrome (73768644686737).

The spelling of 21513504155225 in words is "twenty-one trillion, five hundred thirteen billion, five hundred four million, one hundred fifty-five thousand, two hundred twenty-five".