781052257 has 2 divisors, whose sum is σ = 781052258. Its totient is φ = 781052256.

The previous prime is 781052249. The next prime is 781052281. The reversal of 781052257 is 752250187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 404653456 + 376398801 = 20116^2 + 19401^2 .

It is a cyclic number.

It is not a de Polignac number, because 781052257 - 2³ = 781052249 is a prime.

It is a super-2 number, since 2×781052257² = 1220085256329588098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (781052287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390526128 + 390526129.

It is an arithmetic number, because the mean of its divisors is an integer number (390526129).

Almost surely, 2^781052257 is an apocalyptic number.

It is an amenable number.

781052257 is a deficient number, since it is larger than the sum of its proper divisors (1).

781052257 is an equidigital number, since it uses as much as digits as its factorization.

781052257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 39200, while the sum is 37.

The square root of 781052257 is about 27947.3121605638. The cubic root of 781052257 is about 920.9301623494.

The spelling of 781052257 in words is "seven hundred eighty-one million, fifty-two thousand, two hundred fifty-seven".