138561616 has 20 divisors (see below), whose sum is σ = 268738132. Its totient is φ = 69209856.

The previous prime is 138561613. The next prime is 138561629. The reversal of 138561616 is 616165831.

It can be written as a sum of positive squares in 2 ways, for example, as 79210000 + 59351616 = 8900^2 + 7704^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138561613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13996 + ... + 21748.

Almost surely, 2^138561616 is an apocalyptic number.

138561616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

138561616 is a deficient number, since it is larger than the sum of its proper divisors (130176516).

138561616 is a wasteful number, since it uses less digits than its factorization.

138561616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8878 (or 8872 counting only the distinct ones).

The product of its digits is 25920, while the sum is 37.

The square root of 138561616 is about 11771.2198178439. The cubic root of 138561616 is about 517.4649992275.

It can be divided in two parts, 1385 and 61616, that added together give a square (63001 = 251²).

The spelling of 138561616 in words is "one hundred thirty-eight million, five hundred sixty-one thousand, six hundred sixteen".