261221842 has 48 divisors (see below), whose sum is σ = 489032640. Its totient is φ = 104019552.

The previous prime is 261221819. The next prime is 261221929. The reversal of 261221842 is 248122162.

It is a self number, because there is not a number n which added to its sum of digits gives 261221842.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97363 + ... + 100009.

It is an arithmetic number, because the mean of its divisors is an integer number (10188180).

Almost surely, 2^261221842 is an apocalyptic number.

261221842 is a deficient number, since it is larger than the sum of its proper divisors (227810798).

261221842 is a wasteful number, since it uses less digits than its factorization.

261221842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2735 (or 2728 counting only the distinct ones).

The product of its digits is 3072, while the sum is 28.

The square root of 261221842 is about 16162.3588006207. The cubic root of 261221842 is about 639.2486642038.

The spelling of 261221842 in words is "two hundred sixty-one million, two hundred twenty-one thousand, eight hundred forty-two".