257473781 has 2 divisors, whose sum is σ = 257473782. Its totient is φ = 257473780.

The previous prime is 257473771. The next prime is 257473859. The reversal of 257473781 is 187374752.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150454756 + 107019025 = 12266^2 + 10345^2 .

It is a cyclic number.

It is not a de Polignac number, because 257473781 - 2⁶ = 257473717 is a prime.

It is a super-3 number, since 3×257473781³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (257473751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128736890 + 128736891.

It is an arithmetic number, because the mean of its divisors is an integer number (128736891).

Almost surely, 2^257473781 is an apocalyptic number.

It is an amenable number.

257473781 is a deficient number, since it is larger than the sum of its proper divisors (1).

257473781 is an equidigital number, since it uses as much as digits as its factorization.

257473781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 329280, while the sum is 44.

The square root of 257473781 is about 16045.9895612580. The cubic root of 257473781 is about 636.1765699446.

The spelling of 257473781 in words is "two hundred fifty-seven million, four hundred seventy-three thousand, seven hundred eighty-one".