91685092190521 has 4 divisors (see below), whose sum is σ = 91715281555492. Its totient is φ = 91654902825552.

The previous prime is 91685092190473. The next prime is 91685092190557. The reversal of 91685092190521 is 12509129058619.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 82681557843600 + 9003534346921 = 9092940^2 + 3000589^2 .

It is a cyclic number.

It is not a de Polignac number, because 91685092190521 - 2⁹ = 91685092190009 is a prime.

It is a super-2 number, since 2×91685092190521² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91685092190561) 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, 15094677930 + ... + 15094684003.

It is an arithmetic number, because the mean of its divisors is an integer number (22928820388873).

Almost surely, 2^{91685092190521} is an apocalyptic number.

It is an amenable number.

91685092190521 is a deficient number, since it is larger than the sum of its proper divisors (30189364971).

91685092190521 is a wasteful number, since it uses less digits than its factorization.

91685092190521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30189364970.

The product of its (nonzero) digits is 3499200, while the sum is 58.

The spelling of 91685092190521 in words is "ninety-one trillion, six hundred eighty-five billion, ninety-two million, one hundred ninety thousand, five hundred twenty-one".