61211065205 has 4 divisors (see below), whose sum is σ = 73453278252. Its totient is φ = 48968852160.

The previous prime is 61211065193. The next prime is 61211065211. The reversal of 61211065205 is 50256011216.

It is a happy number.

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 25780155844 + 35430909361 = 160562^2 + 188231^2 .

It is not a de Polignac number, because 61211065205 - 2⁴ = 61211065189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6121106516 + ... + 6121106525.

It is an arithmetic number, because the mean of its divisors is an integer number (18363319563).

Almost surely, 2^61211065205 is an apocalyptic number.

It is an amenable number.

61211065205 is a deficient number, since it is larger than the sum of its proper divisors (12242213047).

61211065205 is a wasteful number, since it uses less digits than its factorization.

61211065205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12242213046.

The product of its (nonzero) digits is 3600, while the sum is 29.

The spelling of 61211065205 in words is "sixty-one billion, two hundred eleven million, sixty-five thousand, two hundred five".