866124921 has 4 divisors (see below), whose sum is σ = 1154833232. Its totient is φ = 577416612.

The previous prime is 866124913. The next prime is 866124929. The reversal of 866124921 is 129421668.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (866124913) and next prime (866124929).

It is not a de Polignac number, because 866124921 - 2³ = 866124913 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 866124921.

It is not an unprimeable number, because it can be changed into a prime (866124929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144354151 + ... + 144354156.

It is an arithmetic number, because the mean of its divisors is an integer number (288708308).

Almost surely, 2^866124921 is an apocalyptic number.

It is an amenable number.

866124921 is a deficient number, since it is larger than the sum of its proper divisors (288708311).

866124921 is a wasteful number, since it uses less digits than its factorization.

866124921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288708310.

The product of its digits is 41472, while the sum is 39.

The square root of 866124921 is about 29430.0003567788. Note that the first 3 decimals coincide. The cubic root of 866124921 is about 953.2208025547.

The spelling of 866124921 in words is "eight hundred sixty-six million, one hundred twenty-four thousand, nine hundred twenty-one".