61111111 has 2 divisors, whose sum is σ = 61111112. Its totient is φ = 61111110.

The previous prime is 61111103. The next prime is 61111121. The reversal of 61111111 is 11111116.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61111111 - 2³ = 61111103 is a prime.

61111111 is a modest number, since divided by 11111 gives 611 as remainder.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 61111091 and 61111100.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61111121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30555555 + 30555556.

It is an arithmetic number, because the mean of its divisors is an integer number (30555556).

Almost surely, 2^61111111 is an apocalyptic number.

61111111 is a deficient number, since it is larger than the sum of its proper divisors (1).

61111111 is an equidigital number, since it uses as much as digits as its factorization.

61111111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6, while the sum is 13.

The square root of 61111111 is about 7817.3595925990. The cubic root of 61111111 is about 393.8885832504. Note that the first 3 decimals are identical.

Adding to 61111111 its reverse (11111116), we get a palindrome (72222227).

It can be divided in two parts, 6 and 1111111, that multiplied together give a palindrome (6666666).

The spelling of 61111111 in words is "sixty-one million, one hundred eleven thousand, one hundred eleven".