20801891 has 8 divisors (see below), whose sum is σ = 22726704. Its totient is φ = 18882720.

The previous prime is 20801873. The next prime is 20801909. The reversal of 20801891 is 19810802.

It is an interprime number because it is at equal distance from previous prime (20801873) and next prime (20801909).

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

It is a cyclic number.

It is not a de Polignac number, because 20801891 - 2¹⁰ = 20800867 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20801191) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11441 + ... + 13133.

It is an arithmetic number, because the mean of its divisors is an integer number (2840838).

Almost surely, 2^20801891 is an apocalyptic number.

20801891 is a deficient number, since it is larger than the sum of its proper divisors (1924813).

20801891 is a wasteful number, since it uses less digits than its factorization.

20801891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2821.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 20801891 is about 4560.9090102742. The cubic root of 20801891 is about 275.0221073136.

The spelling of 20801891 in words is "twenty million, eight hundred one thousand, eight hundred ninety-one".