209216640 has 64 divisors (see below), whose sum is σ = 666884160. Its totient is φ = 55790592.

The previous prime is 209216627. The next prime is 209216647. The reversal of 209216640 is 46612902.

209216640 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (64).

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

It is a junction number, because it is equal to n+sod(n) for n = 209216598 and 209216607.

It is not an unprimeable number, because it can be changed into a prime (209216647) 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, 52564 + ... + 56403.

It is an arithmetic number, because the mean of its divisors is an integer number (10420065).

Almost surely, 2^209216640 is an apocalyptic number.

209216640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

209216640 is an abundant number, since it is smaller than the sum of its proper divisors (457667520).

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

209216640 is a wasteful number, since it uses less digits than its factorization.

209216640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108989 (or 108977 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 209216640 is about 14464.3230052429. The cubic root of 209216640 is about 593.6521901303.

The spelling of 209216640 in words is "two hundred nine million, two hundred sixteen thousand, six hundred forty".