90668021 has 8 divisors (see below), whose sum is σ = 97576344. Its totient is φ = 83934720.

The previous prime is 90667999. The next prime is 90668033. The reversal of 90668021 is 12086609.

It can be written as a sum of positive squares in 4 ways, for example, as 13912900 + 76755121 = 3730^2 + 8761^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 90668021 - 2⁶ = 90667957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90668321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42680 + ... + 44753.

It is an arithmetic number, because the mean of its divisors is an integer number (12197043).

Almost surely, 2^90668021 is an apocalyptic number.

It is an amenable number.

90668021 is a deficient number, since it is larger than the sum of its proper divisors (6908323).

90668021 is a wasteful number, since it uses less digits than its factorization.

90668021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87511.

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 90668021 is about 9521.9756878497. The cubic root of 90668021 is about 449.2465102380.

The spelling of 90668021 in words is "ninety million, six hundred sixty-eight thousand, twenty-one".