91009620 has 288 divisors, whose sum is σ = 330220800. Its totient is φ = 20072448.

The previous prime is 91009579. The next prime is 91009631. The reversal of 91009620 is 2690019.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1022536 + ... + 1022624.

It is an arithmetic number, because the mean of its divisors is an integer number (1146600).

Almost surely, 2^91009620 is an apocalyptic number.

91009620 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 91009620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165110400).

91009620 is an abundant number, since it is smaller than the sum of its proper divisors (239211180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91009620 is a wasteful number, since it uses less digits than its factorization.

91009620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 91009620 is about 9539.8962258507. The cubic root of 91009620 is about 449.8099938580.

Adding to 91009620 its reverse (2690019), we get a palindrome (93699639).

It can be divided in two parts, 910096 and 20, that added together give a square (910116 = 954²).

The spelling of 91009620 in words is "ninety-one million, nine thousand, six hundred twenty".