20891849 has 8 divisors (see below), whose sum is σ = 23990880. Its totient is φ = 17992800.

The previous prime is 20891831. The next prime is 20891879. The reversal of 20891849 is 94819802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20891849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20891809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49772 + ... + 50189.

It is an arithmetic number, because the mean of its divisors is an integer number (2998860).

Almost surely, 2^20891849 is an apocalyptic number.

It is an amenable number.

20891849 is a deficient number, since it is larger than the sum of its proper divisors (3099031).

20891849 is a wasteful number, since it uses less digits than its factorization.

20891849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99991.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 20891849 is about 4570.7602212323. The cubic root of 20891849 is about 275.4179825530.

The spelling of 20891849 in words is "twenty million, eight hundred ninety-one thousand, eight hundred forty-nine".