921812428 has 12 divisors (see below), whose sum is σ = 1619170560. Its totient is φ = 459192272.

The previous prime is 921812407. The next prime is 921812453. The reversal of 921812428 is 824218129.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 427276 + ... + 429427.

It is an arithmetic number, because the mean of its divisors is an integer number (134930880).

Almost surely, 2^921812428 is an apocalyptic number.

It is an amenable number.

921812428 is a deficient number, since it is larger than the sum of its proper divisors (697358132).

921812428 is a wasteful number, since it uses less digits than its factorization.

921812428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856976 (or 856974 counting only the distinct ones).

The product of its digits is 18432, while the sum is 37.

The square root of 921812428 is about 30361.3640668531. The cubic root of 921812428 is about 973.2270838026.

The spelling of 921812428 in words is "nine hundred twenty-one million, eight hundred twelve thousand, four hundred twenty-eight".