721897647 has 8 divisors (see below), whose sum is σ = 1013189760. Its totient is φ = 455935320.

The previous prime is 721897643. The next prime is 721897661. The reversal of 721897647 is 746798127.

721897647 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721897647 - 2² = 721897643 is a prime.

It is a super-2 number, since 2×721897647² = 1042272425488273218, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 721897647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721897643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6332379 + ... + 6332492.

It is an arithmetic number, because the mean of its divisors is an integer number (126648720).

Almost surely, 2^721897647 is an apocalyptic number.

721897647 is a deficient number, since it is larger than the sum of its proper divisors (291292113).

721897647 is a wasteful number, since it uses less digits than its factorization.

721897647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12664893.

The product of its digits is 1185408, while the sum is 51.

The square root of 721897647 is about 26868.1530254686. The cubic root of 721897647 is about 897.0676774575.

The spelling of 721897647 in words is "seven hundred twenty-one million, eight hundred ninety-seven thousand, six hundred forty-seven".