1238265721 has 27 divisors (see below), whose sum is σ = 1586756367. Its totient is φ = 962771040.

The previous prime is 1238265719. The next prime is 1238265727. The reversal of 1238265721 is 1275628321.

The square root of 1238265721 is 35189.

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., 1070925625 + 167340096 = 32725^2 + 12936^2 .

It is not a de Polignac number, because 1238265721 - 2¹ = 1238265719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1238265727) 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 26 ways as a sum of consecutive naturals, for example, 2709325 + ... + 2709781.

Almost surely, 2^1238265721 is an apocalyptic number.

1238265721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1238265721 is the 35189-th square number.

1238265721 is the 17595-th centered octagonal number.

It is an amenable number.

1238265721 is a deficient number, since it is larger than the sum of its proper divisors (348490646).

1238265721 is an frugal number, since it uses more digits than its factorization.

1238265721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 950 (or 475 counting only the distinct ones).

The product of its digits is 40320, while the sum is 37.

The cubic root of 1238265721 is about 1073.8359770298.

The spelling of 1238265721 in words is "one billion, two hundred thirty-eight million, two hundred sixty-five thousand, seven hundred twenty-one".