921981418 has 8 divisors (see below), whose sum is σ = 1384134948. Its totient is φ = 460603104.

The previous prime is 921981407. The next prime is 921981419. The reversal of 921981418 is 814189129.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 845820889 + 76160529 = 29083^2 + 8727^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (921981419) 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 3 ways as a sum of consecutive naturals, for example, 190821 + ... + 195592.

Almost surely, 2^921981418 is an apocalyptic number.

921981418 is a deficient number, since it is larger than the sum of its proper divisors (462153530).

921981418 is a wasteful number, since it uses less digits than its factorization.

921981418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387608.

The product of its digits is 41472, while the sum is 43.

The square root of 921981418 is about 30364.1469170468. The cubic root of 921981418 is about 973.2865520092.

The spelling of 921981418 in words is "nine hundred twenty-one million, nine hundred eighty-one thousand, four hundred eighteen".