20890791 has 20 divisors (see below), whose sum is σ = 31339000. Its totient is φ = 13868496.

The previous prime is 20890789. The next prime is 20890799. The reversal of 20890791 is 19709802.

It is a happy number.

It is not a de Polignac number, because 20890791 - 2¹ = 20890789 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20890799) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 27900 + ... + 28638.

It is an arithmetic number, because the mean of its divisors is an integer number (1566950).

Almost surely, 2^20890791 is an apocalyptic number.

20890791 is a deficient number, since it is larger than the sum of its proper divisors (10448209).

20890791 is an equidigital number, since it uses as much as digits as its factorization.

20890791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100 (or 1091 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 20890791 is about 4570.6444840963. The cubic root of 20890791 is about 275.4133332574.

The spelling of 20890791 in words is "twenty million, eight hundred ninety thousand, seven hundred ninety-one".