21205220325 has 24 divisors (see below), whose sum is σ = 35553099456. Its totient is φ = 11150160000.

The previous prime is 21205220293. The next prime is 21205220327. The reversal of 21205220325 is 52302250212.

It is not a de Polignac number, because 21205220325 - 2⁵ = 21205220293 is a prime.

It is a super-2 number, since 2×21205220325² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21205220295 and 21205220304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205220327) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1985776 + ... + 1996425.

It is an arithmetic number, because the mean of its divisors is an integer number (1481379144).

Almost surely, 2^21205220325 is an apocalyptic number.

21205220325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21205220325 is a deficient number, since it is larger than the sum of its proper divisors (14347879131).

21205220325 is a wasteful number, since it uses less digits than its factorization.

21205220325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3982285 (or 3982280 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

Adding to 21205220325 its reverse (52302250212), we get a palindrome (73507470537).

The spelling of 21205220325 in words is "twenty-one billion, two hundred five million, two hundred twenty thousand, three hundred twenty-five".