20491843 has 2 divisors, whose sum is σ = 20491844. Its totient is φ = 20491842.

The previous prime is 20491829. The next prime is 20491847. The reversal of 20491843 is 34819402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20491843 - 2⁵ = 20491811 is a prime.

It is not a weakly prime, because it can be changed into another prime (20491847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10245921 + 10245922.

It is an arithmetic number, because the mean of its divisors is an integer number (10245922).

Almost surely, 2^20491843 is an apocalyptic number.

20491843 is a deficient number, since it is larger than the sum of its proper divisors (1).

20491843 is an equidigital number, since it uses as much as digits as its factorization.

20491843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 20491843 is about 4526.7916894861. The cubic root of 20491843 is about 273.6488789235.

The spelling of 20491843 in words is "twenty million, four hundred ninety-one thousand, eight hundred forty-three".