209769081 has 4 divisors (see below), whose sum is σ = 279692112. Its totient is φ = 139846052.

The previous prime is 209769073. The next prime is 209769097. The reversal of 209769081 is 180967902.

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 209769081 - 2³ = 209769073 is a prime.

It is a super-2 number, since 2×209769081² = 88006134687169122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (209769031) 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, 34961511 + ... + 34961516.

It is an arithmetic number, because the mean of its divisors is an integer number (69923028).

Almost surely, 2^209769081 is an apocalyptic number.

It is an amenable number.

209769081 is a deficient number, since it is larger than the sum of its proper divisors (69923031).

209769081 is an equidigital number, since it uses as much as digits as its factorization.

209769081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69923030.

The product of its (nonzero) digits is 54432, while the sum is 42.

The square root of 209769081 is about 14483.4070922556. The cubic root of 209769081 is about 594.1742479877.

The spelling of 209769081 in words is "two hundred nine million, seven hundred sixty-nine thousand, eighty-one".