720405581 has 4 divisors (see below), whose sum is σ = 823320672. Its totient is φ = 617490492.

The previous prime is 720405571. The next prime is 720405589. The reversal of 720405581 is 185504027.

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 720405581 - 2²² = 716211277 is a prime.

It is a super-2 number, since 2×720405581² = 1037968402271895122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720405589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51457535 + ... + 51457548.

It is an arithmetic number, because the mean of its divisors is an integer number (205830168).

Almost surely, 2^720405581 is an apocalyptic number.

It is an amenable number.

720405581 is a deficient number, since it is larger than the sum of its proper divisors (102915091).

720405581 is a wasteful number, since it uses less digits than its factorization.

720405581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102915090.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 720405581 is about 26840.3722217111. The cubic root of 720405581 is about 896.4492114819.

The spelling of 720405581 in words is "seven hundred twenty million, four hundred five thousand, five hundred eighty-one".