90991991901 has 8 divisors (see below), whose sum is σ = 121324354144. Its totient is φ = 60660478800.

The previous prime is 90991991863. The next prime is 90991991929. The reversal of 90991991901 is 10919919909.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 90991991901 - 2⁷ = 90991991773 is a prime.

It is a super-2 number, since 2×90991991901² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90991991801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105870 + ... + 439536.

It is an arithmetic number, because the mean of its divisors is an integer number (15165544268).

Almost surely, 2^90991991901 is an apocalyptic number.

It is an amenable number.

90991991901 is a deficient number, since it is larger than the sum of its proper divisors (30332362243).

90991991901 is a wasteful number, since it uses less digits than its factorization.

90991991901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424571.

The product of its (nonzero) digits is 531441, while the sum is 57.

It can be divided in two parts, 909919 and 91901, that added together give a triangular number (1001820 = T₁₄₁₅).

The spelling of 90991991901 in words is "ninety billion, nine hundred ninety-one million, nine hundred ninety-one thousand, nine hundred one".