21629801116225 has 9 divisors (see below), whose sum is σ = 26820982219017. Its totient is φ = 17303822289840.

The previous prime is 21629801116211. The next prime is 21629801116237. The reversal of 21629801116225 is 52261110892612.

It is a happy number.

The square root of 21629801116225 is 4650785.

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

It can be written as a sum of positive squares in 4 ways, for example, as 609996926529 + 21019804189696 = 781023^2 + 4584736^2 .

It is not a de Polignac number, because 21629801116225 - 2¹⁹ = 21629800591937 is a prime.

It is a Duffinian number.

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 8 ways as a sum of consecutive naturals, for example, 22788847 + ... + 23719003.

Almost surely, 2^{21629801116225} is an apocalyptic number.

21629801116225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21629801116225 is the 4650785-th square number.

21629801116225 is the 2325393-rd centered octagonal number.

It is an amenable number.

21629801116225 is a deficient number, since it is larger than the sum of its proper divisors (5191181102792).

21629801116225 is an frugal number, since it uses more digits than its factorization.

21629801116225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1860324 (or 930162 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 46.

The spelling of 21629801116225 in words is "twenty-one trillion, six hundred twenty-nine billion, eight hundred one million, one hundred sixteen thousand, two hundred twenty-five".