21211245225 has 144 divisors (see below), whose sum is σ = 40279366400. Its totient is φ = 11063070720.

The previous prime is 21211245161. The next prime is 21211245281. The reversal of 21211245225 is 52254211212.

21211245225 is a `hidden beast` number, since 2 + 12 + 1 + 124 + 522 + 5 = 666.

It is not a de Polignac number, because 21211245225 - 2⁶ = 21211245161 is a prime.

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

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 143 ways as a sum of consecutive naturals, for example, 92625411 + ... + 92625639.

Almost surely, 2^21211245225 is an apocalyptic number.

21211245225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21211245225 is a deficient number, since it is larger than the sum of its proper divisors (19068121175).

21211245225 is a wasteful number, since it uses less digits than its factorization.

21211245225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526 (or 509 counting only the distinct ones).

The product of its digits is 3200, while the sum is 27.

Adding to 21211245225 its reverse (52254211212), we get a palindrome (73465456437).

The spelling of 21211245225 in words is "twenty-one billion, two hundred eleven million, two hundred forty-five thousand, two hundred twenty-five".