91821540229 has 4 divisors (see below), whose sum is σ = 91822598784. Its totient is φ = 91820481676.

The previous prime is 91821540191. The next prime is 91821540247. The reversal of 91821540229 is 92204512819.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92204512819 = 1733 ⋅53205143.

It is a cyclic number.

It is not a de Polignac number, because 91821540229 - 2⁷ = 91821540101 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 (91821540269) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 386287 + ... + 576940.

It is an arithmetic number, because the mean of its divisors is an integer number (22955649696).

Almost surely, 2^91821540229 is an apocalyptic number.

It is an amenable number.

91821540229 is a deficient number, since it is larger than the sum of its proper divisors (1058555).

91821540229 is an equidigital number, since it uses as much as digits as its factorization.

91821540229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1058554.

The product of its (nonzero) digits is 103680, while the sum is 43.

The spelling of 91821540229 in words is "ninety-one billion, eight hundred twenty-one million, five hundred forty thousand, two hundred twenty-nine".