123872021 has 32 divisors (see below), whose sum is σ = 160124160. Its totient is φ = 93187584.

The previous prime is 123872009. The next prime is 123872051. The reversal of 123872021 is 120278321.

It is not a de Polignac number, because 123872021 - 2¹⁰ = 123870997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123872051) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 192326 + ... + 192968.

It is an arithmetic number, because the mean of its divisors is an integer number (5003880).

Almost surely, 2^123872021 is an apocalyptic number.

It is an amenable number.

123872021 is a deficient number, since it is larger than the sum of its proper divisors (36252139).

123872021 is a wasteful number, since it uses less digits than its factorization.

123872021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 765.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 123872021 is about 11129.7808154518. The cubic root of 123872021 is about 498.4914813199.

The spelling of 123872021 in words is "one hundred twenty-three million, eight hundred seventy-two thousand, twenty-one".