21047434225 has 12 divisors (see below), whose sum is σ = 26392066380. Its totient is φ = 16648755200.

The previous prime is 21047434217. The next prime is 21047434237. The reversal of 21047434225 is 52243474012.

It can be written as a sum of positive squares in 6 ways, for example, as 568679409 + 20478754816 = 23847^2 + 143104^2 .

It is not a de Polignac number, because 21047434225 - 2³ = 21047434217 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4727536 + ... + 4731985.

It is an arithmetic number, because the mean of its divisors is an integer number (2199338865).

Almost surely, 2^21047434225 is an apocalyptic number.

21047434225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21047434225 is a deficient number, since it is larger than the sum of its proper divisors (5344632155).

21047434225 is an equidigital number, since it uses as much as digits as its factorization.

21047434225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9459620 (or 9459615 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 34.

The spelling of 21047434225 in words is "twenty-one billion, forty-seven million, four hundred thirty-four thousand, two hundred twenty-five".