21143493541 has 2 divisors, whose sum is σ = 21143493542. Its totient is φ = 21143493540.

The previous prime is 21143493499. The next prime is 21143493557. The reversal of 21143493541 is 14539434112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20648253025 + 495240516 = 143695^2 + 22254^2 .

It is a cyclic number.

It is not a de Polignac number, because 21143493541 - 2¹¹ = 21143491493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21143493541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21143493941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10571746770 + 10571746771.

It is an arithmetic number, because the mean of its divisors is an integer number (10571746771).

Almost surely, 2^21143493541 is an apocalyptic number.

It is an amenable number.

21143493541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21143493541 is an equidigital number, since it uses as much as digits as its factorization.

21143493541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 37.

The spelling of 21143493541 in words is "twenty-one billion, one hundred forty-three million, four hundred ninety-three thousand, five hundred forty-one".