209161920 has 224 divisors, whose sum is σ = 750539520. Its totient is φ = 48885760.

The previous prime is 209161919. The next prime is 209161921. The reversal of 209161920 is 29161902.

It is a happy number.

209161920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (209161919) and next prime (209161921).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209161921) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 305899 + ... + 306581.

Almost surely, 2^209161920 is an apocalyptic number.

209161920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 209161920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (375269760).

209161920 is an abundant number, since it is smaller than the sum of its proper divisors (541377600).

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

209161920 is a wasteful number, since it uses less digits than its factorization.

209161920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 743 (or 733 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 209161920 is about 14462.4313308655. The cubic root of 209161920 is about 593.6004296197.

The spelling of 209161920 in words is "two hundred nine million, one hundred sixty-one thousand, nine hundred twenty".