20891151 has 6 divisors (see below), whose sum is σ = 30176120. Its totient is φ = 13927428.

The previous prime is 20891149. The next prime is 20891161. The reversal of 20891151 is 15119802.

It is not a de Polignac number, because 20891151 - 2¹ = 20891149 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 (20891131) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1160611 + ... + 1160628.

Almost surely, 2^20891151 is an apocalyptic number.

20891151 is a deficient number, since it is larger than the sum of its proper divisors (9284969).

20891151 is a wasteful number, since it uses less digits than its factorization.

20891151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2321245 (or 2321242 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 20891151 is about 4570.6838656814. The cubic root of 20891151 is about 275.4149152659.

It can be divided in two parts, 2089 and 1151, that added together give a triangular number (3240 = T₈₀).

The spelling of 20891151 in words is "twenty million, eight hundred ninety-one thousand, one hundred fifty-one".