720567521 has 4 divisors (see below), whose sum is σ = 725751600. Its totient is φ = 715383444.

The previous prime is 720567517. The next prime is 720567539. The reversal of 720567521 is 125765027.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 720567521 - 2² = 720567517 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (720567511) 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, 2591831 + ... + 2592108.

It is an arithmetic number, because the mean of its divisors is an integer number (181437900).

Almost surely, 2^720567521 is an apocalyptic number.

It is an amenable number.

720567521 is a deficient number, since it is larger than the sum of its proper divisors (5184079).

720567521 is a wasteful number, since it uses less digits than its factorization.

720567521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5184078.

The product of its (nonzero) digits is 29400, while the sum is 35.

The square root of 720567521 is about 26843.3887763822. The cubic root of 720567521 is about 896.5163774011.

The spelling of 720567521 in words is "seven hundred twenty million, five hundred sixty-seven thousand, five hundred twenty-one".