721969989 has 8 divisors (see below), whose sum is σ = 1036674912. Its totient is φ = 444289200.

The previous prime is 721969973. The next prime is 721970003. The reversal of 721969989 is 989969127.

It is a happy number.

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

It is not a de Polignac number, because 721969989 - 2⁴ = 721969973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721969949) 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, 9255987 + ... + 9256064.

It is an arithmetic number, because the mean of its divisors is an integer number (129584364).

Almost surely, 2^721969989 is an apocalyptic number.

It is an amenable number.

721969989 is a deficient number, since it is larger than the sum of its proper divisors (314704923).

721969989 is a wasteful number, since it uses less digits than its factorization.

721969989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18512067.

The product of its digits is 4408992, while the sum is 60.

The square root of 721969989 is about 26869.4992324010. The cubic root of 721969989 is about 897.0976417711.

The spelling of 721969989 in words is "seven hundred twenty-one million, nine hundred sixty-nine thousand, nine hundred eighty-nine".