720233521 has 4 divisors (see below), whose sum is σ = 823124032. Its totient is φ = 617343012.

The previous prime is 720233491. The next prime is 720233539. The reversal of 720233521 is 125332027.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 125332027 = 2083 ⋅60169.

It is a cyclic number.

It is not a de Polignac number, because 720233521 - 2¹⁵ = 720200753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720233021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51445245 + ... + 51445258.

It is an arithmetic number, because the mean of its divisors is an integer number (205781008).

Almost surely, 2^720233521 is an apocalyptic number.

It is an amenable number.

720233521 is a deficient number, since it is larger than the sum of its proper divisors (102890511).

720233521 is a wasteful number, since it uses less digits than its factorization.

720233521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102890510.

The product of its (nonzero) digits is 2520, while the sum is 25.

The square root of 720233521 is about 26837.1667841447. The cubic root of 720233521 is about 896.3778371817.

Adding to 720233521 its reverse (125332027), we get a palindrome (845565548).

The spelling of 720233521 in words is "seven hundred twenty million, two hundred thirty-three thousand, five hundred twenty-one".