821255291 has 4 divisors (see below), whose sum is σ = 821496312. Its totient is φ = 821014272.

The previous prime is 821255233. The next prime is 821255371. The reversal of 821255291 is 192552128.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-821255291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (821275291) 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, 115325 + ... + 122238.

It is an arithmetic number, because the mean of its divisors is an integer number (205374078).

Almost surely, 2^821255291 is an apocalyptic number.

821255291 is a deficient number, since it is larger than the sum of its proper divisors (241021).

821255291 is a wasteful number, since it uses less digits than its factorization.

821255291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241020.

The product of its digits is 14400, while the sum is 35.

The square root of 821255291 is about 28657.5520761980. The cubic root of 821255291 is about 936.4675366990.

The spelling of 821255291 in words is "eight hundred twenty-one million, two hundred fifty-five thousand, two hundred ninety-one".