729086021 has 6 divisors (see below), whose sum is σ = 774496530. Its totient is φ = 686198336.

The previous prime is 729086009. The next prime is 729086093. The reversal of 729086021 is 120680927.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 515517025 + 213568996 = 22705^2 + 14614^2 .

It is a de Polignac number, because none of the positive numbers 2^k-729086021 is a prime.

It is a super-2 number, since 2×729086021² = 1063132852035224882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (729086321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1261106 + ... + 1261683.

It is an arithmetic number, because the mean of its divisors is an integer number (129082755).

Almost surely, 2^729086021 is an apocalyptic number.

It is an amenable number.

729086021 is a deficient number, since it is larger than the sum of its proper divisors (45410509).

729086021 is a wasteful number, since it uses less digits than its factorization.

729086021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2522823 (or 2522806 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 729086021 is about 27001.5929344918. The cubic root of 729086021 is about 900.0353981962.

The spelling of 729086021 in words is "seven hundred twenty-nine million, eighty-six thousand, twenty-one".