729388781 has 4 divisors (see below), whose sum is σ = 795696864. Its totient is φ = 663080700.

The previous prime is 729388741. The next prime is 729388783. The reversal of 729388781 is 187883927.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-729388781 is a prime.

It is a super-2 number, since 2×729388781² = 1064015987697331922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (729388783) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33154025 + ... + 33154046.

It is an arithmetic number, because the mean of its divisors is an integer number (198924216).

Almost surely, 2^729388781 is an apocalyptic number.

It is an amenable number.

729388781 is a deficient number, since it is larger than the sum of its proper divisors (66308083).

729388781 is a wasteful number, since it uses less digits than its factorization.

729388781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66308082.

The product of its digits is 1354752, while the sum is 53.

The square root of 729388781 is about 27007.1986884979. The cubic root of 729388781 is about 900.1599637478.

The spelling of 729388781 in words is "seven hundred twenty-nine million, three hundred eighty-eight thousand, seven hundred eighty-one".