812540665 has 16 divisors (see below), whose sum is σ = 1042263936. Its totient is φ = 606601600.

The previous prime is 812540639. The next prime is 812540689. The reversal of 812540665 is 566045218.

It is not a de Polignac number, because 812540665 - 2⁷ = 812540537 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81451 + ... + 90880.

It is an arithmetic number, because the mean of its divisors is an integer number (65141496).

Almost surely, 2^812540665 is an apocalyptic number.

It is an amenable number.

812540665 is a deficient number, since it is larger than the sum of its proper divisors (229723271).

812540665 is a wasteful number, since it uses less digits than its factorization.

812540665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172400.

The product of its (nonzero) digits is 57600, while the sum is 37.

The square root of 812540665 is about 28505.0989298406. The cubic root of 812540665 is about 933.1433563873.

The spelling of 812540665 in words is "eight hundred twelve million, five hundred forty thousand, six hundred sixty-five".