721906889 has 32 divisors (see below), whose sum is σ = 864138240. Its totient is φ = 596332800.

The previous prime is 721906807. The next prime is 721906907. The reversal of 721906889 is 988609127.

721906889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 721906889 - 2¹² = 721902793 is a prime.

It is a super-2 number, since 2×721906889² = 1042299112771316642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721906189) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 364907 + ... + 366879.

It is an arithmetic number, because the mean of its divisors is an integer number (27004320).

Almost surely, 2^721906889 is an apocalyptic number.

It is an amenable number.

721906889 is a deficient number, since it is larger than the sum of its proper divisors (142231351).

721906889 is a wasteful number, since it uses less digits than its factorization.

721906889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2081.

The product of its (nonzero) digits is 435456, while the sum is 50.

The square root of 721906889 is about 26868.3250129218. The cubic root of 721906889 is about 897.0715056383.

The spelling of 721906889 in words is "seven hundred twenty-one million, nine hundred six thousand, eight hundred eighty-nine".