61551261 has 6 divisors (see below), whose sum is σ = 88907390. Its totient is φ = 41034168.

The previous prime is 61551233. The next prime is 61551263. The reversal of 61551261 is 16215516.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 36360900 + 25190361 = 6030^2 + 5019^2 .

It is a de Polignac number, because none of the positive numbers 2^k-61551261 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61551263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3419506 + ... + 3419523.

Almost surely, 2^61551261 is an apocalyptic number.

It is an amenable number.

61551261 is a deficient number, since it is larger than the sum of its proper divisors (27356129).

61551261 is a wasteful number, since it uses less digits than its factorization.

61551261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6839035 (or 6839032 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 61551261 is about 7845.4611719134. The cubic root of 61551261 is about 394.8319768201.

Adding to 61551261 its reverse (16215516), we get a palindrome (77766777).

The spelling of 61551261 in words is "sixty-one million, five hundred fifty-one thousand, two hundred sixty-one".