720997663 has 4 divisors (see below), whose sum is σ = 721503640. Its totient is φ = 720491688.

The previous prime is 720997649. The next prime is 720997679. The reversal of 720997663 is 366799027.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-720997663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720997603) 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, 250845 + ... + 253702.

It is an arithmetic number, because the mean of its divisors is an integer number (180375910).

Almost surely, 2^720997663 is an apocalyptic number.

720997663 is a deficient number, since it is larger than the sum of its proper divisors (505977).

720997663 is a wasteful number, since it uses less digits than its factorization.

720997663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505976.

The product of its (nonzero) digits is 857304, while the sum is 49.

The square root of 720997663 is about 26851.3996469458. The cubic root of 720997663 is about 896.6947334090.

The spelling of 720997663 in words is "seven hundred twenty million, nine hundred ninety-seven thousand, six hundred sixty-three".