61866817 has 2 divisors, whose sum is σ = 61866818. Its totient is φ = 61866816.

The previous prime is 61866811. The next prime is 61866821. The reversal of 61866817 is 71866816.

61866817 is nontrivially palindromic in base 13.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 44302336 + 17564481 = 6656^2 + 4191^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61866817 is a prime.

It is a super-2 number, since 2×61866817² = 7655006091422978, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (61866811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30933408 + 30933409.

It is an arithmetic number, because the mean of its divisors is an integer number (30933409).

Almost surely, 2^61866817 is an apocalyptic number.

It is an amenable number.

61866817 is a deficient number, since it is larger than the sum of its proper divisors (1).

61866817 is an equidigital number, since it uses as much as digits as its factorization.

61866817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96768, while the sum is 43.

The square root of 61866817 is about 7865.5461984531. The cubic root of 61866817 is about 395.5055578660.

Subtracting 61866817 from its reverse (71866816), we obtain a palindrome (9999999).

The spelling of 61866817 in words is "sixty-one million, eight hundred sixty-six thousand, eight hundred seventeen".