91821053671 has 2 divisors, whose sum is σ = 91821053672. Its totient is φ = 91821053670.

The previous prime is 91821053657. The next prime is 91821053689. The reversal of 91821053671 is 17635012819.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91821053671 is a prime.

It is a super-2 number, since 2×91821053671² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91821033671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45910526835 + 45910526836.

It is an arithmetic number, because the mean of its divisors is an integer number (45910526836).

Almost surely, 2^91821053671 is an apocalyptic number.

91821053671 is a deficient number, since it is larger than the sum of its proper divisors (1).

91821053671 is an equidigital number, since it uses as much as digits as its factorization.

91821053671 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 91821053671 in words is "ninety-one billion, eight hundred twenty-one million, fifty-three thousand, six hundred seventy-one".