1684221261 has 4 divisors (see below), whose sum is σ = 2245628352. Its totient is φ = 1122814172.

The previous prime is 1684221251. The next prime is 1684221293. The reversal of 1684221261 is 1621224861.

It is a happy number.

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 1684221261 - 2¹⁸ = 1683959117 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1684221211) 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, 280703541 + ... + 280703546.

It is an arithmetic number, because the mean of its divisors is an integer number (561407088).

Almost surely, 2^1684221261 is an apocalyptic number.

It is an amenable number.

1684221261 is a deficient number, since it is larger than the sum of its proper divisors (561407091).

1684221261 is an equidigital number, since it uses as much as digits as its factorization.

1684221261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561407090.

The product of its digits is 9216, while the sum is 33.

The square root of 1684221261 is about 41039.2648691470. The cubic root of 1684221261 is about 1189.7792262800.

The spelling of 1684221261 in words is "one billion, six hundred eighty-four million, two hundred twenty-one thousand, two hundred sixty-one".