728901781 has 4 divisors (see below), whose sum is σ = 729860364. Its totient is φ = 727943200.

The previous prime is 728901779. The next prime is 728901793. The reversal of 728901781 is 187109827.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 226021156 + 502880625 = 15034^2 + 22425^2 .

It is a cyclic number.

It is not a de Polignac number, because 728901781 - 2¹ = 728901779 is a prime.

It is a super-2 number, since 2×728901781² = 1062595612689943922, 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 (728901721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 478150 + ... + 479671.

It is an arithmetic number, because the mean of its divisors is an integer number (182465091).

Almost surely, 2^728901781 is an apocalyptic number.

It is an amenable number.

728901781 is a deficient number, since it is larger than the sum of its proper divisors (958583).

728901781 is an equidigital number, since it uses as much as digits as its factorization.

728901781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958582.

The product of its (nonzero) digits is 56448, while the sum is 43.

The square root of 728901781 is about 26998.1810683609. The cubic root of 728901781 is about 899.9595788431.

The spelling of 728901781 in words is "seven hundred twenty-eight million, nine hundred one thousand, seven hundred eighty-one".