61128981 has 12 divisors (see below), whose sum is σ = 89964108. Its totient is φ = 39983424.

The previous prime is 61128979. The next prime is 61129001. The reversal of 61128981 is 18982116.

It can be written as a sum of positive squares in 2 ways, for example, as 45684081 + 15444900 = 6759^2 + 3930^2 .

It is not a de Polignac number, because 61128981 - 2¹ = 61128979 is a prime.

It is a super-2 number, since 2×61128981² = 7473504636196722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61128961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63600 + ... + 64553.

It is an arithmetic number, because the mean of its divisors is an integer number (7497009).

Almost surely, 2^61128981 is an apocalyptic number.

It is an amenable number.

61128981 is a deficient number, since it is larger than the sum of its proper divisors (28835127).

61128981 is a wasteful number, since it uses less digits than its factorization.

61128981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128212 (or 128209 counting only the distinct ones).

The product of its digits is 6912, while the sum is 36.

The square root of 61128981 is about 7818.5024780964. The cubic root of 61128981 is about 393.9269729033.

It can be divided in two parts, 611 and 28981, that added together give a palindrome (29592).

The spelling of 61128981 in words is "sixty-one million, one hundred twenty-eight thousand, nine hundred eighty-one".