725278781 has 2 divisors, whose sum is σ = 725278782. Its totient is φ = 725278780.

The previous prime is 725278751. The next prime is 725278793. The reversal of 725278781 is 187872527.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 413756281 + 311522500 = 20341^2 + 17650^2 .

It is a cyclic number.

It is not a de Polignac number, because 725278781 - 2⁶ = 725278717 is a prime.

It is a super-2 number, since 2×725278781² = 1052058620337691922, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (725278751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 362639390 + 362639391.

It is an arithmetic number, because the mean of its divisors is an integer number (362639391).

Almost surely, 2^725278781 is an apocalyptic number.

It is an amenable number.

725278781 is a deficient number, since it is larger than the sum of its proper divisors (1).

725278781 is an equidigital number, since it uses as much as digits as its factorization.

725278781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 439040, while the sum is 47.

The square root of 725278781 is about 26931.0003713193. Note that the first 3 decimals coincide. The cubic root of 725278781 is about 898.4660210959.

The spelling of 725278781 in words is "seven hundred twenty-five million, two hundred seventy-eight thousand, seven hundred eighty-one".