820991417 has 4 divisors (see below), whose sum is σ = 856686720. Its totient is φ = 785296116.

The previous prime is 820991411. The next prime is 820991453. The reversal of 820991417 is 714199028.

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 820991417 - 2¹⁰ = 820990393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820991411) 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, 17847617 + ... + 17847662.

It is an arithmetic number, because the mean of its divisors is an integer number (214171680).

Almost surely, 2^820991417 is an apocalyptic number.

It is an amenable number.

820991417 is a deficient number, since it is larger than the sum of its proper divisors (35695303).

820991417 is a wasteful number, since it uses less digits than its factorization.

820991417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35695302.

The product of its (nonzero) digits is 36288, while the sum is 41.

The square root of 820991417 is about 28652.9477890147. The cubic root of 820991417 is about 936.3672285049.

The spelling of 820991417 in words is "eight hundred twenty million, nine hundred ninety-one thousand, four hundred seventeen".