21490446936841 has 3 divisors (see below), whose sum is σ = 21490451572621. Its totient is φ = 21490442301062.

The previous prime is 21490446936733. The next prime is 21490446936877. The reversal of 21490446936841 is 14863964409412.

The square root of 21490446936841 is 4635779.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 21490446936841 - 2¹³ = 21490446928649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21490446936841.

It is not an unprimeable number, because it can be changed into a prime (21490446936341) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2317890 + ... + 6953668.

Almost surely, 2^{21490446936841} is an apocalyptic number.

21490446936841 is the 4635779-th square number.

21490446936841 is the 2317890-th centered octagonal number.

It is an amenable number.

21490446936841 is a deficient number, since it is larger than the sum of its proper divisors (4635780).

21490446936841 is an frugal number, since it uses more digits than its factorization.

21490446936841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9271558 (or 4635779 counting only the distinct ones).

The product of its (nonzero) digits is 35831808, while the sum is 61.

The spelling of 21490446936841 in words is "twenty-one trillion, four hundred ninety billion, four hundred forty-six million, nine hundred thirty-six thousand, eight hundred forty-one".