921861 has 20 divisors (see below), whose sum is σ = 1452000. Its totient is φ = 581256.

The previous prime is 921841. The next prime is 921871. The reversal of 921861 is 168129.

It is not a de Polignac number, because 921861 - 2⁷ = 921733 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

921861 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 921861.

It is not an unprimeable number, because it can be changed into a prime (921821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1240 + ... + 1838.

It is an arithmetic number, because the mean of its divisors is an integer number (72600).

2⁹²¹⁸⁶¹ is an apocalyptic number.

It is an amenable number.

921861 is a deficient number, since it is larger than the sum of its proper divisors (530139).

921861 is a wasteful number, since it uses less digits than its factorization.

921861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630 (or 621 counting only the distinct ones).

The product of its digits is 864, while the sum is 27.

The square root of 921861 is about 960.1359278769. The cubic root of 921861 is about 97.3244177213.

921861 divided by its sum of digits (27) gives a palindrome (34143).

It can be divided in two parts, 92 and 1861, that added together give a triangular number (1953 = T₆₂).

The spelling of 921861 in words is "nine hundred twenty-one thousand, eight hundred sixty-one".