21568255487 has 16 divisors (see below), whose sum is σ = 23925537792. Its totient is φ = 19351474560.

The previous prime is 21568255459. The next prime is 21568255519. The reversal of 21568255487 is 78455286512.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21568255487 - 2¹² = 21568251391 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21568255447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270113 + ... + 340730.

It is an arithmetic number, because the mean of its divisors is an integer number (1495346112).

Almost surely, 2^21568255487 is an apocalyptic number.

21568255487 is a deficient number, since it is larger than the sum of its proper divisors (2357282305).

21568255487 is a wasteful number, since it uses less digits than its factorization.

21568255487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 610958.

The product of its digits is 5376000, while the sum is 53.

The spelling of 21568255487 in words is "twenty-one billion, five hundred sixty-eight million, two hundred fifty-five thousand, four hundred eighty-seven".