21980659 has 2 divisors, whose sum is σ = 21980660. Its totient is φ = 21980658.

The previous prime is 21980657. The next prime is 21980671. The reversal of 21980659 is 95608912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21980659 - 2¹ = 21980657 is a prime.

Together with 21980657, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21980653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10990329 + 10990330.

It is an arithmetic number, because the mean of its divisors is an integer number (10990330).

Almost surely, 2^21980659 is an apocalyptic number.

21980659 is a deficient number, since it is larger than the sum of its proper divisors (1).

21980659 is an equidigital number, since it uses as much as digits as its factorization.

21980659 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 21980659 is about 4688.3535489551. The cubic root of 21980659 is about 280.1217965022.

The spelling of 21980659 in words is "twenty-one million, nine hundred eighty thousand, six hundred fifty-nine".