123821809 has 8 divisors (see below), whose sum is σ = 125330112. Its totient is φ = 122322960.

The previous prime is 123821801. The next prime is 123821813. The reversal of 123821809 is 908128321.

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

It is a cyclic number.

It is not a de Polignac number, because 123821809 - 2³ = 123821801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123821801) 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, 26004 + ... + 30394.

It is an arithmetic number, because the mean of its divisors is an integer number (15666264).

Almost surely, 2^123821809 is an apocalyptic number.

It is an amenable number.

123821809 is a deficient number, since it is larger than the sum of its proper divisors (1508303).

123821809 is a wasteful number, since it uses less digits than its factorization.

123821809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4727.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 123821809 is about 11127.5248370875. The cubic root of 123821809 is about 498.4241170707.

The spelling of 123821809 in words is "one hundred twenty-three million, eight hundred twenty-one thousand, eight hundred nine".