139255561 has 4 divisors (see below), whose sum is σ = 139304452. Its totient is φ = 139206672.

The previous prime is 139255559. The next prime is 139255583. The reversal of 139255561 is 165552931.

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 126787600 + 12467961 = 11260^2 + 3531^2 .

It is a cyclic number.

It is not a de Polignac number, because 139255561 - 2¹ = 139255559 is a prime.

It is a super-2 number, since 2×139255561² = 38784222538849442, which 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 139255561.

It is not an unprimeable number, because it can be changed into a prime (139255511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19890 + ... + 25963.

It is an arithmetic number, because the mean of its divisors is an integer number (34826113).

Almost surely, 2^139255561 is an apocalyptic number.

It is an amenable number.

139255561 is a deficient number, since it is larger than the sum of its proper divisors (48891).

139255561 is an equidigital number, since it uses as much as digits as its factorization.

139255561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48890.

The product of its digits is 40500, while the sum is 37.

The square root of 139255561 is about 11800.6593459857. The cubic root of 139255561 is about 518.3274180618.

It can be divided in two parts, 1392 and 55561, that added together give a triangular number (56953 = T₃₃₇).

The spelling of 139255561 in words is "one hundred thirty-nine million, two hundred fifty-five thousand, five hundred sixty-one".