136778521 has 12 divisors (see below), whose sum is σ = 151148116. Its totient is φ = 123678720.

The previous prime is 136778519. The next prime is 136778561. The reversal of 136778521 is 125877631.

It can be written as a sum of positive squares in 2 ways, for example, as 87216921 + 49561600 = 9339^2 + 7040^2 .

It is not a de Polignac number, because 136778521 - 2¹ = 136778519 is a prime.

It is a hoax number, since the sum of its digits (40) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (136778561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20425 + ... + 26281.

Almost surely, 2^136778521 is an apocalyptic number.

136778521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

136778521 is a deficient number, since it is larger than the sum of its proper divisors (14369595).

136778521 is a wasteful number, since it uses less digits than its factorization.

136778521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6072 (or 6061 counting only the distinct ones).

The product of its digits is 70560, while the sum is 40.

The square root of 136778521 is about 11695.2349698499. The cubic root of 136778521 is about 515.2357245575.

The spelling of 136778521 in words is "one hundred thirty-six million, seven hundred seventy-eight thousand, five hundred twenty-one".