921808458 has 64 divisors (see below), whose sum is σ = 2121799680. Its totient is φ = 296445744.

The previous prime is 921808457. The next prime is 921808469. The reversal of 921808458 is 854808129.

It is a happy number.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (921808451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 190335 + ... + 195117.

It is an arithmetic number, because the mean of its divisors is an integer number (33153120).

Almost surely, 2^921808458 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 921808458, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1060899840).

921808458 is an abundant number, since it is smaller than the sum of its proper divisors (1199991222).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

921808458 is a wasteful number, since it uses less digits than its factorization.

921808458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4920 (or 4914 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The square root of 921808458 is about 30361.2986876385. The cubic root of 921808458 is about 973.2256866575.

The spelling of 921808458 in words is "nine hundred twenty-one million, eight hundred eight thousand, four hundred fifty-eight".