61513215553 has 4 divisors (see below), whose sum is σ = 61687474308. Its totient is φ = 61338956800.

The previous prime is 61513215529. The next prime is 61513215563. The reversal of 61513215553 is 35551231516.

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 33365771569 + 28147443984 = 182663^2 + 167772^2 .

It is a cyclic number.

It is not a de Polignac number, because 61513215553 - 2²¹ = 61511118401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61513215563) 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 3 ways as a sum of consecutive naturals, for example, 87128848 + ... + 87129553.

It is an arithmetic number, because the mean of its divisors is an integer number (15421868577).

Almost surely, 2^61513215553 is an apocalyptic number.

It is an amenable number.

61513215553 is a deficient number, since it is larger than the sum of its proper divisors (174258755).

61513215553 is a wasteful number, since it uses less digits than its factorization.

61513215553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174258754.

The product of its digits is 67500, while the sum is 37.

The spelling of 61513215553 in words is "sixty-one billion, five hundred thirteen million, two hundred fifteen thousand, five hundred fifty-three".