20990890891044 has 120 divisors (see below), whose sum is σ = 55561962871800. Its totient is φ = 6909827959296.

The previous prime is 20990890891043. The next prime is 20990890891051. The reversal of 20990890891044 is 44019809809902.

It can be written as a sum of positive squares in 4 ways, for example, as 4056349065444 + 16934541825600 = 2014038^2 + 4115160^2 .

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (20990890891043) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7095072 + ... + 9608424.

It is an arithmetic number, because the mean of its divisors is an integer number (463016357265).

Almost surely, 2^{20990890891044} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20990890891044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27780981435900).

20990890891044 is an abundant number, since it is smaller than the sum of its proper divisors (34571071980756).

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

20990890891044 is a wasteful number, since it uses less digits than its factorization.

20990890891044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2513691 (or 2513680 counting only the distinct ones).

The product of its (nonzero) digits is 13436928, while the sum is 63.

The spelling of 20990890891044 in words is "twenty trillion, nine hundred ninety billion, eight hundred ninety million, eight hundred ninety-one thousand, forty-four".