21487005679 has 2 divisors, whose sum is σ = 21487005680. Its totient is φ = 21487005678.

The previous prime is 21487005677. The next prime is 21487005689. The reversal of 21487005679 is 97650078412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21487005679 - 2¹ = 21487005677 is a prime.

Together with 21487005677, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21487005677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10743502839 + 10743502840.

It is an arithmetic number, because the mean of its divisors is an integer number (10743502840).

Almost surely, 2^21487005679 is an apocalyptic number.

21487005679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21487005679 is an equidigital number, since it uses as much as digits as its factorization.

21487005679 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 846720, while the sum is 49.

The spelling of 21487005679 in words is "twenty-one billion, four hundred eighty-seven million, five thousand, six hundred seventy-nine".