61816081 has 8 divisors (see below), whose sum is σ = 64359720. Its totient is φ = 59299968.

The previous prime is 61816067. The next prime is 61816093. The reversal of 61816081 is 18061816.

61816081 = 5559² + 5560².

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 19501056 + 42315025 = 4416^2 + 6505^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 61816081 - 2⁵ = 61816049 is a prime.

It is a super-2 number, since 2×61816081² = 7642455740397122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61816021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2236 + ... + 11341.

It is an arithmetic number, because the mean of its divisors is an integer number (8044965).

Almost surely, 2^61816081 is an apocalyptic number.

61816081 is the 5560-th centered square number.

It is an amenable number.

61816081 is a deficient number, since it is larger than the sum of its proper divisors (2543639).

61816081 is a wasteful number, since it uses less digits than its factorization.

61816081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13763.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 61816081 is about 7862.3203318105. The cubic root of 61816081 is about 395.3974123429.

Adding to 61816081 its reverse (18061816), we get a palindrome (79877897).

The spelling of 61816081 in words is "sixty-one million, eight hundred sixteen thousand, eighty-one".