21345304625 has 16 divisors (see below), whose sum is σ = 27358917456. Its totient is φ = 16614720000.

The previous prime is 21345304621. The next prime is 21345304627. The reversal of 21345304625 is 52640354312.

It can be written as a sum of positive squares in 8 ways, for example, as 5678526736 + 15666777889 = 75356^2 + 125167^2 .

It is not a de Polignac number, because 21345304625 - 2² = 21345304621 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21345304621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2302976 + ... + 2312225.

It is an arithmetic number, because the mean of its divisors is an integer number (1709932341).

Almost surely, 2^21345304625 is an apocalyptic number.

21345304625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21345304625 is a deficient number, since it is larger than the sum of its proper divisors (6013612831).

21345304625 is an equidigital number, since it uses as much as digits as its factorization.

21345304625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4615253 (or 4615243 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 35.

Adding to 21345304625 its reverse (52640354312), we get a palindrome (73985658937).

The spelling of 21345304625 in words is "twenty-one billion, three hundred forty-five million, three hundred four thousand, six hundred twenty-five".