20521450025 has 6 divisors (see below), whose sum is σ = 25446598062. Its totient is φ = 16417160000.

The previous prime is 20521450021. The next prime is 20521450039. The reversal of 20521450025 is 52005412502.

It can be written as a sum of positive squares in 3 ways, for example, as 2078995216 + 18442454809 = 45596^2 + 135803^2 .

It is not a de Polignac number, because 20521450025 - 2² = 20521450021 is a prime.

It is a super-2 number, since 2×20521450025² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20521449976 and 20521450003.

It is not an unprimeable number, because it can be changed into a prime (20521450021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 410428976 + ... + 410429025.

It is an arithmetic number, because the mean of its divisors is an integer number (4241099677).

Almost surely, 2^20521450025 is an apocalyptic number.

20521450025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20521450025 is a deficient number, since it is larger than the sum of its proper divisors (4925148037).

20521450025 is an equidigital number, since it uses as much as digits as its factorization.

20521450025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820858011 (or 820858006 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 26.

Adding to 20521450025 its reverse (52005412502), we get a palindrome (72526862527).

The spelling of 20521450025 in words is "twenty billion, five hundred twenty-one million, four hundred fifty thousand, twenty-five".