61644665 has 4 divisors (see below), whose sum is σ = 73973604. Its totient is φ = 49315728.

The previous prime is 61644617. The next prime is 61644697. The reversal of 61644665 is 56644616.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15077689 + 46566976 = 3883^2 + 6824^2 .

It is a cyclic number.

It is not a de Polignac number, because 61644665 - 2⁸ = 61644409 is a prime.

It is a super-3 number, since 3×61644665³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

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, 6164462 + ... + 6164471.

It is an arithmetic number, because the mean of its divisors is an integer number (18493401).

Almost surely, 2^61644665 is an apocalyptic number.

It is an amenable number.

61644665 is a deficient number, since it is larger than the sum of its proper divisors (12328939).

61644665 is a wasteful number, since it uses less digits than its factorization.

61644665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12328938.

The product of its digits is 103680, while the sum is 38.

The square root of 61644665 is about 7851.4116565112. The cubic root of 61644665 is about 395.0315949731.

The spelling of 61644665 in words is "sixty-one million, six hundred forty-four thousand, six hundred sixty-five".