7209538281 has 81 divisors (see below), whose sum is σ = 11971922781. Its totient is φ = 4177522800.

The previous prime is 7209538249. The next prime is 7209538307. The reversal of 7209538281 is 1828359027.

It is a happy number.

The square root of 7209538281 is 84909.

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

It is not a de Polignac number, because 7209538281 - 2⁵ = 7209538249 is a prime.

It is a super-2 number, since 2×7209538281² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7209538081) by changing a digit.

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 80 ways as a sum of consecutive naturals, for example, 86861866 + ... + 86861948.

Almost surely, 2^7209538281 is an apocalyptic number.

7209538281 is the 84909-th square number.

7209538281 is the 42455-th centered octagonal number.

It is an amenable number.

7209538281 is a deficient number, since it is larger than the sum of its proper divisors (4762384500).

7209538281 is a wasteful number, since it uses less digits than its factorization.

7209538281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256 (or 128 counting only the distinct ones).

The product of its (nonzero) digits is 241920, while the sum is 45.

The cubic root of 7209538281 is about 1931.8310882316.

It can be divided in two parts, 7209 and 538281, that added together give a triangular number (545490 = T₁₀₄₄).

The spelling of 7209538281 in words is "seven billion, two hundred nine million, five hundred thirty-eight thousand, two hundred eighty-one".