209218442 has 24 divisors (see below), whose sum is σ = 338701440. Its totient is φ = 96818040.

The previous prime is 209218433. The next prime is 209218447. The reversal of 209218442 is 244812902.

209218442 = T₂₄₂₈ + T₂₄₂₉ + ... + T₂₄₉₆.

It is a happy number.

209218442 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 209218399 and 209218408.

It is not an unprimeable number, because it can be changed into a prime (209218447) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29609 + ... + 35987.

It is an arithmetic number, because the mean of its divisors is an integer number (14112560).

Almost surely, 2^209218442 is an apocalyptic number.

209218442 is a deficient number, since it is larger than the sum of its proper divisors (129482998).

209218442 is a wasteful number, since it uses less digits than its factorization.

209218442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6458 (or 6435 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 209218442 is about 14464.3852963062. The cubic root of 209218442 is about 593.6538945170.

The spelling of 209218442 in words is "two hundred nine million, two hundred eighteen thousand, four hundred forty-two".