61611997 has 4 divisors (see below), whose sum is σ = 61751520. Its totient is φ = 61472476.

The previous prime is 61611959. The next prime is 61612027. The reversal of 61611997 is 79911616.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61611997 - 2¹⁵ = 61579229 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61611937) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69097 + ... + 69982.

It is an arithmetic number, because the mean of its divisors is an integer number (15437880).

Almost surely, 2^61611997 is an apocalyptic number.

It is an amenable number.

61611997 is a deficient number, since it is larger than the sum of its proper divisors (139523).

61611997 is a wasteful number, since it uses less digits than its factorization.

61611997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139522.

The product of its digits is 20412, while the sum is 40.

The square root of 61611997 is about 7849.3309906004. The cubic root of 61611997 is about 394.9618015724.

The spelling of 61611997 in words is "sixty-one million, six hundred eleven thousand, nine hundred ninety-seven".