20890644340 has 12 divisors (see below), whose sum is σ = 43870353156. Its totient is φ = 8356257728.

The previous prime is 20890644331. The next prime is 20890644373. The reversal of 20890644340 is 4344609802.

It can be written as a sum of positive squares in 2 ways, for example, as 15302184804 + 5588459536 = 123702^2 + 74756^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20890644293 and 20890644302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 522266089 + ... + 522266128.

It is an arithmetic number, because the mean of its divisors is an integer number (3655862763).

Almost surely, 2^20890644340 is an apocalyptic number.

20890644340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20890644340 is an abundant number, since it is smaller than the sum of its proper divisors (22979708816).

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

20890644340 is a wasteful number, since it uses less digits than its factorization.

20890644340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1044532226 (or 1044532224 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 40.

The spelling of 20890644340 in words is "twenty billion, eight hundred ninety million, six hundred forty-four thousand, three hundred forty".