21798571 has 2 divisors, whose sum is σ = 21798572. Its totient is φ = 21798570.

The previous prime is 21798559. The next prime is 21798599. The reversal of 21798571 is 17589712.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21798571 - 2¹⁹ = 21274283 is a prime.

It is not a weakly prime, because it can be changed into another prime (21798521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10899285 + 10899286.

It is an arithmetic number, because the mean of its divisors is an integer number (10899286).

Almost surely, 2^21798571 is an apocalyptic number.

21798571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21798571 is an equidigital number, since it uses as much as digits as its factorization.

21798571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35280, while the sum is 40.

The square root of 21798571 is about 4668.8939803769. The cubic root of 21798571 is about 279.3461401021.

The spelling of 21798571 in words is "twenty-one million, seven hundred ninety-eight thousand, five hundred seventy-one".