61218261 has 24 divisors (see below), whose sum is σ = 98760480. Its totient is φ = 37670832.

The previous prime is 61218257. The next prime is 61218263. The reversal of 61218261 is 16281216.

It is not a de Polignac number, because 61218261 - 2² = 61218257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61218263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6531 + ... + 12848.

It is an arithmetic number, because the mean of its divisors is an integer number (4115020).

Almost surely, 2^61218261 is an apocalyptic number.

It is an amenable number.

61218261 is a deficient number, since it is larger than the sum of its proper divisors (37542219).

61218261 is a wasteful number, since it uses less digits than its factorization.

61218261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19407 (or 19395 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 61218261 is about 7824.2099281653. The cubic root of 61218261 is about 394.1186588074.

Adding to 61218261 its reverse (16281216), we get a palindrome (77499477).

The spelling of 61218261 in words is "sixty-one million, two hundred eighteen thousand, two hundred sixty-one".