90736381721 has 32 divisors (see below), whose sum is σ = 97348759200. Its totient is φ = 84414597120.

The previous prime is 90736381699. The next prime is 90736381751. The reversal of 90736381721 is 12718363709.

It can be written as a sum of positive squares in 16 ways, for example, as 19040964121 + 71695417600 = 137989^2 + 267760^2 .

It is a cyclic number.

It is not a de Polignac number, because 90736381721 - 2²² = 90732187417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90736381751) 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 31 ways as a sum of consecutive naturals, for example, 48340235 + ... + 48342111.

It is an arithmetic number, because the mean of its divisors is an integer number (3042148725).

Almost surely, 2^90736381721 is an apocalyptic number.

It is an amenable number.

90736381721 is a deficient number, since it is larger than the sum of its proper divisors (6612377479).

90736381721 is a wasteful number, since it uses less digits than its factorization.

90736381721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2429.

The product of its (nonzero) digits is 381024, while the sum is 47.

The spelling of 90736381721 in words is "ninety billion, seven hundred thirty-six million, three hundred eighty-one thousand, seven hundred twenty-one".