91220729 has 12 divisors (see below), whose sum is σ = 97657920. Its totient is φ = 85178520.

The previous prime is 91220711. The next prime is 91220743. The reversal of 91220729 is 92702219.

It is not a de Polignac number, because 91220729 - 2¹² = 91216633 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 91220695 and 91220704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91220629) 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 11 ways as a sum of consecutive naturals, for example, 23852 + ... + 27410.

It is an arithmetic number, because the mean of its divisors is an integer number (8138160).

Almost surely, 2^91220729 is an apocalyptic number.

It is an amenable number.

91220729 is a deficient number, since it is larger than the sum of its proper divisors (6437191).

91220729 is a wasteful number, since it uses less digits than its factorization.

91220729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3668 (or 3649 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 91220729 is about 9550.9543502207. The cubic root of 91220729 is about 450.1575234530.

The spelling of 91220729 in words is "ninety-one million, two hundred twenty thousand, seven hundred twenty-nine".