21425205252 has 72 divisors (see below), whose sum is σ = 55226920000. Its totient is φ = 6459773760.

The previous prime is 21425205223. The next prime is 21425205271. The reversal of 21425205252 is 25250252412.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 251874 + ... + 326022.

Almost surely, 2^21425205252 is an apocalyptic number.

21425205252 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21425205252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27613460000).

21425205252 is an abundant number, since it is smaller than the sum of its proper divisors (33801714748).

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

21425205252 is a wasteful number, since it uses less digits than its factorization.

21425205252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74377 (or 74364 counting only the distinct ones).

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

Adding to 21425205252 its reverse (25250252412), we get a palindrome (46675457664).

The spelling of 21425205252 in words is "twenty-one billion, four hundred twenty-five million, two hundred five thousand, two hundred fifty-two".