869921 has 8 divisors (see below), whose sum is σ = 953064. Its totient is φ = 789120.

The previous prime is 869909. The next prime is 869927. The reversal of 869921 is 129968.

It can be written as a sum of positive squares in 4 ways, for example, as 40000 + 829921 = 200^2 + 911^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-869921 is a prime.

It is an Ulam 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 869921.

It is not an unprimeable number, because it can be changed into a prime (869927) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 245 + ... + 1341.

It is an arithmetic number, because the mean of its divisors is an integer number (119133).

2⁸⁶⁹⁹²¹ is an apocalyptic number.

It is an amenable number.

869921 is a deficient number, since it is larger than the sum of its proper divisors (83143).

869921 is a wasteful number, since it uses less digits than its factorization.

869921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1171.

The product of its digits is 7776, while the sum is 35.

The square root of 869921 is about 932.6955559024. The cubic root of 869921 is about 95.4611374819.

The spelling of 869921 in words is "eight hundred sixty-nine thousand, nine hundred twenty-one".