218923997 has 4 divisors (see below), whose sum is σ = 220647936. Its totient is φ = 217200060.

The previous prime is 218923967. The next prime is 218924029. The reversal of 218923997 is 799329812.

218923997 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is not a de Polignac number, because 218923997 - 2⁸ = 218923741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218923927) 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, 861779 + ... + 862032.

It is an arithmetic number, because the mean of its divisors is an integer number (55161984).

Almost surely, 2^218923997 is an apocalyptic number.

It is an amenable number.

218923997 is a deficient number, since it is larger than the sum of its proper divisors (1723939).

218923997 is a wasteful number, since it uses less digits than its factorization.

218923997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1723938.

The product of its digits is 489888, while the sum is 50.

The square root of 218923997 is about 14796.0804607166. The cubic root of 218923997 is about 602.6952789523.

The spelling of 218923997 in words is "two hundred eighteen million, nine hundred twenty-three thousand, nine hundred ninety-seven".