821961 has 16 divisors (see below), whose sum is σ = 1392000. Its totient is φ = 469584.

The previous prime is 821941. The next prime is 821971. The reversal of 821961 is 169128.

It is not a de Polignac number, because 821961 - 2⁶ = 821897 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (821911) 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, 1986 + ... + 2363.

It is an arithmetic number, because the mean of its divisors is an integer number (87000).

2⁸²¹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

821961 is a deficient number, since it is larger than the sum of its proper divisors (570039).

821961 is a wasteful number, since it uses less digits than its factorization.

821961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4365 (or 4359 counting only the distinct ones).

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

The square root of 821961 is about 906.6206483420. The cubic root of 821961 is about 93.6735697066.

The spelling of 821961 in words is "eight hundred twenty-one thousand, nine hundred sixty-one".