21642884479 has 2 divisors, whose sum is σ = 21642884480. Its totient is φ = 21642884478.

The previous prime is 21642884449. The next prime is 21642884519. The reversal of 21642884479 is 97448824612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21642884479 - 2⁹ = 21642883967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21642884449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10821442239 + 10821442240.

It is an arithmetic number, because the mean of its divisors is an integer number (10821442240).

Almost surely, 2^21642884479 is an apocalyptic number.

21642884479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642884479 is an equidigital number, since it uses as much as digits as its factorization.

21642884479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6193152, while the sum is 55.

The spelling of 21642884479 in words is "twenty-one billion, six hundred forty-two million, eight hundred eighty-four thousand, four hundred seventy-nine".