720970913 has 4 divisors (see below), whose sum is σ = 776430228. Its totient is φ = 665511600.

The previous prime is 720970889. The next prime is 720970931. The reversal of 720970913 is 319079027.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 31225744 + 689745169 = 5588^2 + 26263^2 .

It is not a de Polignac number, because 720970913 - 2¹² = 720966817 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 (720970963) 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, 27729638 + ... + 27729663.

It is an arithmetic number, because the mean of its divisors is an integer number (194107557).

Almost surely, 2^720970913 is an apocalyptic number.

It is an amenable number.

720970913 is a deficient number, since it is larger than the sum of its proper divisors (55459315).

720970913 is a wasteful number, since it uses less digits than its factorization.

720970913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55459314.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 720970913 is about 26850.9015304887. The cubic root of 720970913 is about 896.6836437379.

The spelling of 720970913 in words is "seven hundred twenty million, nine hundred seventy thousand, nine hundred thirteen".