209012881 has 32 divisors (see below), whose sum is σ = 274636800. Its totient is φ = 157525200.

The previous prime is 209012861. The next prime is 209012911. The reversal of 209012881 is 188210902.

It is a happy number.

It is not a de Polignac number, because 209012881 - 2¹³ = 209004689 is a prime.

It is a super-2 number, since 2×209012881² = 87372768847840322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (209012861) 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, 116070 + ... + 117856.

It is an arithmetic number, because the mean of its divisors is an integer number (8582400).

Almost surely, 2^209012881 is an apocalyptic number.

It is an amenable number.

209012881 is a deficient number, since it is larger than the sum of its proper divisors (65623919).

209012881 is a wasteful number, since it uses less digits than its factorization.

209012881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1850 (or 1836 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 209012881 is about 14457.2777866374. The cubic root of 209012881 is about 593.4594054858.

The spelling of 209012881 in words is "two hundred nine million, twelve thousand, eight hundred eighty-one".