91428221641 has 9 divisors (see below), whose sum is σ = 92833759431. Its totient is φ = 90043664832.

The previous prime is 91428221609. The next prime is 91428221653. The reversal of 91428221641 is 14612282419.

The square root of 91428221641 is 302371.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 40513225 + 91387708416 = 6365^2 + 302304^2 .

It is not a de Polignac number, because 91428221641 - 2⁵ = 91428221609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 91428221594 and 91428221603.

It is not an unprimeable number, because it can be changed into a prime (91428227641) 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 8 ways as a sum of consecutive naturals, for example, 20256601 + ... + 20261113.

It is an arithmetic number, because the mean of its divisors is an integer number (10314862159).

Almost surely, 2^91428221641 is an apocalyptic number.

91428221641 is the 302371-st square number.

91428221641 is the 151186-th centered octagonal number.

It is an amenable number.

91428221641 is a deficient number, since it is larger than the sum of its proper divisors (1405537790).

91428221641 is an frugal number, since it uses more digits than its factorization.

91428221641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9160 (or 4580 counting only the distinct ones).

The product of its digits is 55296, while the sum is 40.

The spelling of 91428221641 in words is "ninety-one billion, four hundred twenty-eight million, two hundred twenty-one thousand, six hundred forty-one".