209871942 has 32 divisors (see below), whose sum is σ = 481842432. Its totient is φ = 59696544.

The previous prime is 209871931. The next prime is 209871943. The reversal of 209871942 is 249178902.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 209871894 and 209871903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209871943) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1473 + ... + 20540.

It is an arithmetic number, because the mean of its divisors is an integer number (15057576).

Almost surely, 2^209871942 is an apocalyptic number.

209871942 is an abundant number, since it is smaller than the sum of its proper divisors (271970490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

209871942 is a wasteful number, since it uses less digits than its factorization.

209871942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22252.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 209871942 is about 14486.9576516258. The cubic root of 209871942 is about 594.2713505891.

The spelling of 209871942 in words is "two hundred nine million, eight hundred seventy-one thousand, nine hundred forty-two".