816261857 has 4 divisors (see below), whose sum is σ = 816497856. Its totient is φ = 816025860.

The previous prime is 816261833. The next prime is 816261863. The reversal of 816261857 is 758162618.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 816261857 - 2⁸ = 816261601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (816261877) 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, 112733 + ... + 119754.

It is an arithmetic number, because the mean of its divisors is an integer number (204124464).

Almost surely, 2^816261857 is an apocalyptic number.

It is an amenable number.

816261857 is a deficient number, since it is larger than the sum of its proper divisors (235999).

816261857 is a wasteful number, since it uses less digits than its factorization.

816261857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235998.

The product of its digits is 161280, while the sum is 44.

The square root of 816261857 is about 28570.2967607969. The cubic root of 816261857 is about 934.5656926591.

The spelling of 816261857 in words is "eight hundred sixteen million, two hundred sixty-one thousand, eight hundred fifty-seven".