21748091 has 2 divisors, whose sum is σ = 21748092. Its totient is φ = 21748090.

The previous prime is 21748063. The next prime is 21748121. The reversal of 21748091 is 19084712.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21748091 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21748061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10874045 + 10874046.

It is an arithmetic number, because the mean of its divisors is an integer number (10874046).

Almost surely, 2^21748091 is an apocalyptic number.

21748091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21748091 is an equidigital number, since it uses as much as digits as its factorization.

21748091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 21748091 is about 4663.4848557704. The cubic root of 21748091 is about 279.1303416710.

The spelling of 21748091 in words is "twenty-one million, seven hundred forty-eight thousand, ninety-one".