61549681 has 2 divisors, whose sum is σ = 61549682. Its totient is φ = 61549680.

The previous prime is 61549667. The next prime is 61549711. The reversal of 61549681 is 18694516.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54893281 + 6656400 = 7409^2 + 2580^2 .

It is a cyclic number.

It is not a de Polignac number, because 61549681 - 2¹⁵ = 61516913 is a prime.

It is a super-2 number, since 2×61549681² = 7576726462403522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (61540681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30774840 + 30774841.

It is an arithmetic number, because the mean of its divisors is an integer number (30774841).

Almost surely, 2^61549681 is an apocalyptic number.

It is an amenable number.

61549681 is a deficient number, since it is larger than the sum of its proper divisors (1).

61549681 is an equidigital number, since it uses as much as digits as its factorization.

61549681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 40.

The square root of 61549681 is about 7845.3604761031. The cubic root of 61549681 is about 394.8285983902.

The spelling of 61549681 in words is "sixty-one million, five hundred forty-nine thousand, six hundred eighty-one".