261221204 has 6 divisors (see below), whose sum is σ = 457137114. Its totient is φ = 130610600.

The previous prime is 261221203. The next prime is 261221237. The reversal of 261221204 is 402122162.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 174768400 + 86452804 = 13220^2 + 9298^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261221203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32652647 + ... + 32652654.

It is an arithmetic number, because the mean of its divisors is an integer number (76189519).

Almost surely, 2^261221204 is an apocalyptic number.

It is an amenable number.

261221204 is a deficient number, since it is larger than the sum of its proper divisors (195915910).

261221204 is a wasteful number, since it uses less digits than its factorization.

261221204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65305305 (or 65305303 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 261221204 is about 16162.3390633905. The cubic root of 261221204 is about 639.2481437764.

Adding to 261221204 its reverse (402122162), we get a palindrome (663343366).

The spelling of 261221204 in words is "two hundred sixty-one million, two hundred twenty-one thousand, two hundred four".