90078521 has 6 divisors (see below), whose sum is σ = 97540830. Its totient is φ = 83149248.

The previous prime is 90078509. The next prime is 90078539. The reversal of 90078521 is 12587009.

It can be written as a sum of positive squares in 3 ways, for example, as 8880400 + 81198121 = 2980^2 + 9011^2 .

It is not a de Polignac number, because 90078521 - 2²⁶ = 22969657 is a prime.

It is a super-2 number, since 2×90078521² = 16228279891094882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90078551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 266336 + ... + 266673.

It is an arithmetic number, because the mean of its divisors is an integer number (16256805).

Almost surely, 2^90078521 is an apocalyptic number.

It is an amenable number.

90078521 is a deficient number, since it is larger than the sum of its proper divisors (7462309).

90078521 is a wasteful number, since it uses less digits than its factorization.

90078521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533035 (or 533022 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 90078521 is about 9490.9704983210. The cubic root of 90078521 is about 448.2707643213.

The spelling of 90078521 in words is "ninety million, seventy-eight thousand, five hundred twenty-one".