21574879 has 2 divisors, whose sum is σ = 21574880. Its totient is φ = 21574878.

The previous prime is 21574877. The next prime is 21574901. The reversal of 21574879 is 97847512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21574879 - 2¹ = 21574877 is a prime.

Together with 21574877, 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 (21574873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10787439 + 10787440.

It is an arithmetic number, because the mean of its divisors is an integer number (10787440).

Almost surely, 2^21574879 is an apocalyptic number.

21574879 is a deficient number, since it is larger than the sum of its proper divisors (1).

21574879 is an equidigital number, since it uses as much as digits as its factorization.

21574879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141120, while the sum is 43.

The square root of 21574879 is about 4644.8766399120. The cubic root of 21574879 is about 278.3873239194.

The spelling of 21574879 in words is "twenty-one million, five hundred seventy-four thousand, eight hundred seventy-nine".