21450211252 has 6 divisors (see below), whose sum is σ = 37537869698. Its totient is φ = 10725105624.

The previous prime is 21450211163. The next prime is 21450211267. The reversal of 21450211252 is 25211205412.

It can be written as a sum of positive squares in only one way, i.e., 18367296676 + 3082914576 = 135526^2 + 55524^2 .

It is a super-2 number, since 2×21450211252² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2681276403 + ... + 2681276410.

Almost surely, 2^21450211252 is an apocalyptic number.

It is an amenable number.

21450211252 is a deficient number, since it is larger than the sum of its proper divisors (16087658446).

21450211252 is a wasteful number, since it uses less digits than its factorization.

21450211252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5362552817 (or 5362552815 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

Adding to 21450211252 its reverse (25211205412), we get a palindrome (46661416664).

The spelling of 21450211252 in words is "twenty-one billion, four hundred fifty million, two hundred eleven thousand, two hundred fifty-two".