921166787 has 4 divisors (see below), whose sum is σ = 922140456. Its totient is φ = 920193120.

The previous prime is 921166733. The next prime is 921166819. The reversal of 921166787 is 787661129.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 787661129 = 1453 ⋅542093.

It is a cyclic number.

It is not a de Polignac number, because 921166787 - 2¹⁸ = 920904643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (921166187) by changing a digit.

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, 485414 + ... + 487307.

It is an arithmetic number, because the mean of its divisors is an integer number (230535114).

Almost surely, 2^921166787 is an apocalyptic number.

921166787 is a deficient number, since it is larger than the sum of its proper divisors (973669).

921166787 is an equidigital number, since it uses as much as digits as its factorization.

921166787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 973668.

The product of its digits is 254016, while the sum is 47.

The square root of 921166787 is about 30350.7295958433. The cubic root of 921166787 is about 972.9998133925. Note that the first 3 decimals are identical.

The spelling of 921166787 in words is "nine hundred twenty-one million, one hundred sixty-six thousand, seven hundred eighty-seven".