61640685 has 12 divisors (see below), whose sum is σ = 106843932. Its totient is φ = 32875008.

The previous prime is 61640681. The next prime is 61640707. The reversal of 61640685 is 58604616.

61640685 is a `hidden beast` number, since 6 + 1 + 640 + 6 + 8 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 30437289 + 31203396 = 5517^2 + 5586^2 .

It is not a de Polignac number, because 61640685 - 2² = 61640681 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61640681) 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 11 ways as a sum of consecutive naturals, for example, 684852 + ... + 684941.

It is an arithmetic number, because the mean of its divisors is an integer number (8903661).

Almost surely, 2^61640685 is an apocalyptic number.

It is an amenable number.

61640685 is a deficient number, since it is larger than the sum of its proper divisors (45203247).

61640685 is a wasteful number, since it uses less digits than its factorization.

61640685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1369804 (or 1369801 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 61640685 is about 7851.1581948143. The cubic root of 61640685 is about 395.0230932394.

The spelling of 61640685 in words is "sixty-one million, six hundred forty thousand, six hundred eighty-five".