20891701 has 4 divisors (see below), whose sum is σ = 20901312. Its totient is φ = 20882092.

The previous prime is 20891677. The next prime is 20891711. The reversal of 20891701 is 10719802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 10719802 = 2 ⋅5359901.

It is a cyclic number.

It is not a de Polignac number, because 20891701 - 2⁵ = 20891669 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20891701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891711) 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 3 ways as a sum of consecutive naturals, for example, 180 + ... + 6466.

It is an arithmetic number, because the mean of its divisors is an integer number (5225328).

Almost surely, 2^20891701 is an apocalyptic number.

It is an amenable number.

20891701 is a deficient number, since it is larger than the sum of its proper divisors (9611).

20891701 is an equidigital number, since it uses as much as digits as its factorization.

20891701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9610.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20891701 is about 4570.7440313367. The cubic root of 20891701 is about 275.4173321884.

The spelling of 20891701 in words is "twenty million, eight hundred ninety-one thousand, seven hundred one".