21523361425 has 12 divisors (see below), whose sum is σ = 26925157260. Its totient is φ = 17066309120.

The previous prime is 21523361407. The next prime is 21523361471. The reversal of 21523361425 is 52416332512.

It can be written as a sum of positive squares in 6 ways, for example, as 9438316801 + 12085044624 = 97151^2 + 109932^2 .

It is not a de Polignac number, because 21523361425 - 2⁹ = 21523360913 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3806620 + ... + 3812269.

It is an arithmetic number, because the mean of its divisors is an integer number (2243763105).

Almost surely, 2^21523361425 is an apocalyptic number.

21523361425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21523361425 is a deficient number, since it is larger than the sum of its proper divisors (5401795835).

21523361425 is a wasteful number, since it uses less digits than its factorization.

21523361425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7619012 (or 7619007 counting only the distinct ones).

The product of its digits is 43200, while the sum is 34.

Adding to 21523361425 its reverse (52416332512), we get a palindrome (73939693937).

The spelling of 21523361425 in words is "twenty-one billion, five hundred twenty-three million, three hundred sixty-one thousand, four hundred twenty-five".