61278989 has 2 divisors, whose sum is σ = 61278990. Its totient is φ = 61278988.

The previous prime is 61278979. The next prime is 61279021. The reversal of 61278989 is 98987216.

61278989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53042089 + 8236900 = 7283^2 + 2870^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61278989 is a prime.

It is a super-2 number, since 2×61278989² = 7510228985724242, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61278979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30639494 + 30639495.

It is an arithmetic number, because the mean of its divisors is an integer number (30639495).

Almost surely, 2^61278989 is an apocalyptic number.

It is an amenable number.

61278989 is a deficient number, since it is larger than the sum of its proper divisors (1).

61278989 is an equidigital number, since it uses as much as digits as its factorization.

61278989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 50.

The square root of 61278989 is about 7828.0897414376. The cubic root of 61278989 is about 394.2489365369.

The spelling of 61278989 in words is "sixty-one million, two hundred seventy-eight thousand, nine hundred eighty-nine".