209310825025 has 27 divisors (see below), whose sum is σ = 266857660251. Its totient is φ = 162857139840.

The previous prime is 209310825001. The next prime is 209310825079. The reversal of 209310825025 is 520528013902.

The square root of 209310825025 is 457505.

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

It can be written as a sum of positive squares in 13 ways, for example, as 9594790209 + 199716034816 = 97953^2 + 446896^2 .

It is not a de Polignac number, because 209310825025 - 2¹⁹ = 209310300737 is a prime.

It is a super-2 number, since 2×209310825025² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

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, 84637189 + ... + 84639661.

Almost surely, 2^209310825025 is an apocalyptic number.

209310825025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

209310825025 is the 457505-th square number.

209310825025 is the 228753-rd centered octagonal number.

It is an amenable number.

209310825025 is a deficient number, since it is larger than the sum of its proper divisors (57546835226).

209310825025 is an frugal number, since it uses more digits than its factorization.

209310825025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5030 (or 2515 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 37.

Adding to 209310825025 its reverse (520528013902), we get a palindrome (729838838927).

The spelling of 209310825025 in words is "two hundred nine billion, three hundred ten million, eight hundred twenty-five thousand, twenty-five".