21101473825 has 6 divisors (see below), whose sum is σ = 26165827574. Its totient is φ = 16881179040.

The previous prime is 21101473823. The next prime is 21101473829. The reversal of 21101473825 is 52837410112.

It can be written as a sum of positive squares in 3 ways, for example, as 20466576 + 21081007249 = 4524^2 + 145193^2 .

It is not a de Polignac number, because 21101473825 - 2¹ = 21101473823 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21101473823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 422029452 + ... + 422029501.

Almost surely, 2^21101473825 is an apocalyptic number.

21101473825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21101473825 is a deficient number, since it is larger than the sum of its proper divisors (5064353749).

21101473825 is an equidigital number, since it uses as much as digits as its factorization.

21101473825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844058963 (or 844058958 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 34.

Adding to 21101473825 its reverse (52837410112), we get a palindrome (73938883937).

The spelling of 21101473825 in words is "twenty-one billion, one hundred one million, four hundred seventy-three thousand, eight hundred twenty-five".