61807638665 has 16 divisors (see below), whose sum is σ = 76756513680. Its totient is φ = 47722536960.

The previous prime is 61807638661. The next prime is 61807638691. The reversal of 61807638665 is 56683670816.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 9283707904 + 52523930761 = 96352^2 + 229181^2 .

It is not a de Polignac number, because 61807638665 - 2² = 61807638661 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61807638665.

It is not an unprimeable number, because it can be changed into a prime (61807638661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 298025 + ... + 460905.

It is an arithmetic number, because the mean of its divisors is an integer number (4797282105).

Almost surely, 2^61807638665 is an apocalyptic number.

It is an amenable number.

61807638665 is a deficient number, since it is larger than the sum of its proper divisors (14948875015).

61807638665 is a wasteful number, since it uses less digits than its factorization.

61807638665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165532.

The product of its (nonzero) digits is 8709120, while the sum is 56.

The spelling of 61807638665 in words is "sixty-one billion, eight hundred seven million, six hundred thirty-eight thousand, six hundred sixty-five".