21225252252 has 12 divisors (see below), whose sum is σ = 49525588616. Its totient is φ = 7075084080.

The previous prime is 21225252211. The next prime is 21225252253. The reversal of 21225252252 is 25225252212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21225252252² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225252253) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 884385499 + ... + 884385522.

Almost surely, 2^21225252252 is an apocalyptic number.

It is an amenable number.

21225252252 is an abundant number, since it is smaller than the sum of its proper divisors (28300336364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21225252252 is a wasteful number, since it uses less digits than its factorization.

21225252252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1768771028 (or 1768771026 counting only the distinct ones).

The product of its digits is 16000, while the sum is 30.

The spelling of 21225252252 in words is "twenty-one billion, two hundred twenty-five million, two hundred fifty-two thousand, two hundred fifty-two".