812581257 has 4 divisors (see below), whose sum is σ = 1083441680. Its totient is φ = 541720836.

The previous prime is 812581241. The next prime is 812581267. The reversal of 812581257 is 752185218.

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 not a de Polignac number, because 812581257 - 2⁴ = 812581241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (812581267) 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, 135430207 + ... + 135430212.

It is an arithmetic number, because the mean of its divisors is an integer number (270860420).

Almost surely, 2^812581257 is an apocalyptic number.

It is an amenable number.

812581257 is a deficient number, since it is larger than the sum of its proper divisors (270860423).

812581257 is a wasteful number, since it uses less digits than its factorization.

812581257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270860422.

The product of its digits is 44800, while the sum is 39.

The square root of 812581257 is about 28505.8109339131. The cubic root of 812581257 is about 933.1588951068.

The spelling of 812581257 in words is "eight hundred twelve million, five hundred eighty-one thousand, two hundred fifty-seven".