21880847 has 2 divisors, whose sum is σ = 21880848. Its totient is φ = 21880846.

The previous prime is 21880829. The next prime is 21880849. The reversal of 21880847 is 74808812.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21880847 - 2⁸ = 21880591 is a prime.

Together with 21880849, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21880847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21880849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10940423 + 10940424.

It is an arithmetic number, because the mean of its divisors is an integer number (10940424).

Almost surely, 2^21880847 is an apocalyptic number.

21880847 is a deficient number, since it is larger than the sum of its proper divisors (1).

21880847 is an equidigital number, since it uses as much as digits as its factorization.

21880847 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 28672, while the sum is 38.

The square root of 21880847 is about 4677.6967622966. The cubic root of 21880847 is about 279.6971512977.

The spelling of 21880847 in words is "twenty-one million, eight hundred eighty thousand, eight hundred forty-seven".