20891493 has 24 divisors (see below), whose sum is σ = 36005760. Its totient is φ = 11937240.

The previous prime is 20891473. The next prime is 20891503. The reversal of 20891493 is 39419802.

It is not a de Polignac number, because 20891493 - 2⁵ = 20891461 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20891413) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6573 + ... + 9218.

It is an arithmetic number, because the mean of its divisors is an integer number (1500240).

Almost surely, 2^20891493 is an apocalyptic number.

It is an amenable number.

20891493 is a deficient number, since it is larger than the sum of its proper divisors (15114267).

20891493 is a wasteful number, since it uses less digits than its factorization.

20891493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15814 (or 15801 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 20891493 is about 4570.7212778729. The cubic root of 20891493 is about 275.4164181572.

The spelling of 20891493 in words is "twenty million, eight hundred ninety-one thousand, four hundred ninety-three".