720267561 has 36 divisors (see below), whose sum is σ = 1182558468. Its totient is φ = 419888448.

The previous prime is 720267557. The next prime is 720267589. The reversal of 720267561 is 165762027.

720267561 is a `hidden beast` number, since 72 + 0 + 26 + 7 + 561 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 179426025 + 540841536 = 13395^2 + 23256^2 .

It is not a de Polignac number, because 720267561 - 2² = 720267557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720267511) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 33711 + ... + 50763.

Almost surely, 2^720267561 is an apocalyptic number.

It is an amenable number.

720267561 is a deficient number, since it is larger than the sum of its proper divisors (462290907).

720267561 is a wasteful number, since it uses less digits than its factorization.

720267561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17110 (or 17088 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 720267561 is about 26837.8009717637. The cubic root of 720267561 is about 896.3919586298.

The spelling of 720267561 in words is "seven hundred twenty million, two hundred sixty-seven thousand, five hundred sixty-one".