21008334745225 has 27 divisors (see below), whose sum is σ = 26117487821991. Its totient is φ = 16763454699600.

The previous prime is 21008334745213. The next prime is 21008334745241. The reversal of 21008334745225 is 52254743380012.

It is a happy number.

The square root of 21008334745225 is 4583485.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7563000508281 + 13445334236944 = 2750091^2 + 3666788^2 .

It is not a de Polignac number, because 21008334745225 - 2¹⁵ = 21008334712457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 11252454742 + ... + 11252456608.

Almost surely, 2^{21008334745225} is an apocalyptic number.

21008334745225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21008334745225 is the 4583485-th square number.

21008334745225 is the 2291743-rd centered octagonal number.

It is an amenable number.

21008334745225 is a deficient number, since it is larger than the sum of its proper divisors (5109153076766).

21008334745225 is an frugal number, since it uses more digits than its factorization.

21008334745225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4726 (or 2363 counting only the distinct ones).

The product of its (nonzero) digits is 1612800, while the sum is 46.

The spelling of 21008334745225 in words is "twenty-one trillion, eight billion, three hundred thirty-four million, seven hundred forty-five thousand, two hundred twenty-five".