721691089 has 36 divisors (see below), whose sum is σ = 900035584. Its totient is φ = 566721792.

The previous prime is 721691057. The next prime is 721691093. The reversal of 721691089 is 980196127.

It is not a de Polignac number, because 721691089 - 2⁵ = 721691057 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721691039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5682544 + ... + 5682670.

Almost surely, 2^721691089 is an apocalyptic number.

It is an amenable number.

721691089 is a deficient number, since it is larger than the sum of its proper divisors (178344495).

721691089 is a wasteful number, since it uses less digits than its factorization.

721691089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 43.

The square root of 721691089 is about 26864.3088316078. The cubic root of 721691089 is about 896.9821093801.

The spelling of 721691089 in words is "seven hundred twenty-one million, six hundred ninety-one thousand, eighty-nine".