61506661013 has 4 divisors (see below), whose sum is σ = 70293326880. Its totient is φ = 52719995148.

The previous prime is 61506660989. The next prime is 61506661037. The reversal of 61506661013 is 31016660516.

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 an interprime number because it is at equal distance from previous prime (61506660989) and next prime (61506661037).

It is a cyclic number.

It is not a de Polignac number, because 61506661013 - 2²⁰ = 61505612437 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 (61506661093) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4393332923 + ... + 4393332936.

It is an arithmetic number, because the mean of its divisors is an integer number (17573331720).

Almost surely, 2^61506661013 is an apocalyptic number.

It is an amenable number.

61506661013 is a deficient number, since it is larger than the sum of its proper divisors (8786665867).

61506661013 is an equidigital number, since it uses as much as digits as its factorization.

61506661013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8786665866.

The product of its (nonzero) digits is 19440, while the sum is 35.

The spelling of 61506661013 in words is "sixty-one billion, five hundred six million, six hundred sixty-one thousand, thirteen".