209451090 has 16 divisors (see below), whose sum is σ = 502682688. Its totient is φ = 55853616.

The previous prime is 209451029. The next prime is 209451091. The reversal of 209451090 is 90154902.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 6981703 = 209451090 / (2 + 0 + 9 + 4 + 5 + 1 + 0 + 9 + 0).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (209451091) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3490822 + ... + 3490881.

It is an arithmetic number, because the mean of its divisors is an integer number (31417668).

Almost surely, 2^209451090 is an apocalyptic number.

209451090 is an abundant number, since it is smaller than the sum of its proper divisors (293231598).

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

209451090 is a wasteful number, since it uses less digits than its factorization.

209451090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6981713.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 209451090 is about 14472.4251595923. The cubic root of 209451090 is about 593.8738579653.

The spelling of 209451090 in words is "two hundred nine million, four hundred fifty-one thousand, ninety".