61278357209 has 4 divisors (see below), whose sum is σ = 61282121700. Its totient is φ = 61274592720.

The previous prime is 61278357197. The next prime is 61278357227. The reversal of 61278357209 is 90275387216.

61278357209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 4906302025 + 56372055184 = 70045^2 + 237428^2 .

It is a cyclic number.

It is not a de Polignac number, because 61278357209 - 2⁴ = 61278357193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61278357289) 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, 1857722 + ... + 1890419.

It is an arithmetic number, because the mean of its divisors is an integer number (15320530425).

Almost surely, 2^61278357209 is an apocalyptic number.

It is an amenable number.

61278357209 is a deficient number, since it is larger than the sum of its proper divisors (3764491).

61278357209 is a wasteful number, since it uses less digits than its factorization.

61278357209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3764490.

The product of its (nonzero) digits is 1270080, while the sum is 50.

The spelling of 61278357209 in words is "sixty-one billion, two hundred seventy-eight million, three hundred fifty-seven thousand, two hundred nine".