15721543 has 2 divisors, whose sum is σ = 15721544. Its totient is φ = 15721542.

The previous prime is 15721487. The next prime is 15721579. The reversal of 15721543 is 34512751.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 15721543 - 2¹³ = 15713351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15721843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7860771 + 7860772.

It is an arithmetic number, because the mean of its divisors is an integer number (7860772).

Almost surely, 2^15721543 is an apocalyptic number.

15721543 is a deficient number, since it is larger than the sum of its proper divisors (1).

15721543 is an equidigital number, since it uses as much as digits as its factorization.

15721543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4200, while the sum is 28.

The square root of 15721543 is about 3965.0401006799. The cubic root of 15721543 is about 250.5138391537.

The spelling of 15721543 in words is "fifteen million, seven hundred twenty-one thousand, five hundred forty-three".