921000891 has 16 divisors (see below), whose sum is σ = 1356770304. Its totient is φ = 552756864.

The previous prime is 921000887. The next prime is 921000907. The reversal of 921000891 is 198000129.

It is not a de Polignac number, because 921000891 - 2² = 921000887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (921000811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 391411 + ... + 393756.

It is an arithmetic number, because the mean of its divisors is an integer number (84798144).

Almost surely, 2^921000891 is an apocalyptic number.

921000891 is a deficient number, since it is larger than the sum of its proper divisors (435769413).

921000891 is a wasteful number, since it uses less digits than its factorization.

921000891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785210.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 921000891 is about 30347.9964907076. The cubic root of 921000891 is about 972.9413996249.

The spelling of 921000891 in words is "nine hundred twenty-one million, eight hundred ninety-one", and thus it is an aban number.