90408178721 has 16 divisors (see below), whose sum is σ = 104245886976. Its totient is φ = 76802309136.

The previous prime is 90408178661. The next prime is 90408178723. The reversal of 90408178721 is 12787180409.

It is a happy number.

It is not a de Polignac number, because 90408178721 - 2¹⁴ = 90408162337 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90408178723) 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 15 ways as a sum of consecutive naturals, for example, 807080 + ... + 912246.

It is an arithmetic number, because the mean of its divisors is an integer number (6515367936).

Almost surely, 2^90408178721 is an apocalyptic number.

It is an amenable number.

90408178721 is a deficient number, since it is larger than the sum of its proper divisors (13837708255).

90408178721 is a wasteful number, since it uses less digits than its factorization.

90408178721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106268.

The product of its (nonzero) digits is 225792, while the sum is 47.

The spelling of 90408178721 in words is "ninety billion, four hundred eight million, one hundred seventy-eight thousand, seven hundred twenty-one".