61660509501 has 4 divisors (see below), whose sum is σ = 82214012672. Its totient is φ = 41107006332.

The previous prime is 61660509461. The next prime is 61660509539. The reversal of 61660509501 is 10590506616.

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 not a de Polignac number, because 61660509501 - 2¹⁰ = 61660508477 is a prime.

It is a super-2 number, since 2×61660509501² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61660509501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61660507501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10276751581 + ... + 10276751586.

It is an arithmetic number, because the mean of its divisors is an integer number (20553503168).

Almost surely, 2^61660509501 is an apocalyptic number.

It is an amenable number.

61660509501 is a deficient number, since it is larger than the sum of its proper divisors (20553503171).

61660509501 is a wasteful number, since it uses less digits than its factorization.

61660509501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20553503170.

The product of its (nonzero) digits is 48600, while the sum is 39.

The spelling of 61660509501 in words is "sixty-one billion, six hundred sixty million, five hundred nine thousand, five hundred one".