21535503487 has 2 divisors, whose sum is σ = 21535503488. Its totient is φ = 21535503486.

The previous prime is 21535503419. The next prime is 21535503547. The reversal of 21535503487 is 78430553512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21535503487 - 2¹⁹ = 21534979199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21535543487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767751743 + 10767751744.

It is an arithmetic number, because the mean of its divisors is an integer number (10767751744).

Almost surely, 2^21535503487 is an apocalyptic number.

21535503487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21535503487 is an equidigital number, since it uses as much as digits as its factorization.

21535503487 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504000, while the sum is 43.

The spelling of 21535503487 in words is "twenty-one billion, five hundred thirty-five million, five hundred three thousand, four hundred eighty-seven".