21503250025 has 12 divisors (see below), whose sum is σ = 26665891612. Its totient is φ = 17201399040.

The previous prime is 21503250011. The next prime is 21503250031. The reversal of 21503250025 is 52005230512.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1519752256 + 19983497769 = 38984^2 + 141363^2 .

It is not a de Polignac number, because 21503250025 - 2⁵ = 21503249993 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

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, 571597 + ... + 608053.

Almost surely, 2^21503250025 is an apocalyptic number.

21503250025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21503250025 is a deficient number, since it is larger than the sum of its proper divisors (5162641587).

21503250025 is a wasteful number, since it uses less digits than its factorization.

21503250025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60060 (or 60055 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 25.

Adding to 21503250025 its reverse (52005230512), we get a palindrome (73508480537).

The spelling of 21503250025 in words is "twenty-one billion, five hundred three million, two hundred fifty thousand, twenty-five".