213720123 has 4 divisors (see below), whose sum is σ = 284960168. Its totient is φ = 142480080.

The previous prime is 213720109. The next prime is 213720127. The reversal of 213720123 is 321027312.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 213720123 - 2¹³ = 213711931 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 213720123.

It is not an unprimeable number, because it can be changed into a prime (213720127) 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, 35620018 + ... + 35620023.

It is an arithmetic number, because the mean of its divisors is an integer number (71240042).

Almost surely, 2^213720123 is an apocalyptic number.

213720123 is a deficient number, since it is larger than the sum of its proper divisors (71240045).

213720123 is an equidigital number, since it uses as much as digits as its factorization.

213720123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71240044.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 213720123 is about 14619.1697096655. The cubic root of 213720123 is about 597.8815317347.

Adding to 213720123 its reverse (321027312), we get a palindrome (534747435).

The spelling of 213720123 in words is "two hundred thirteen million, seven hundred twenty thousand, one hundred twenty-three".