21013191 has 12 divisors (see below), whose sum is σ = 31672368. Its totient is φ = 13399584.

The previous prime is 21013189. The next prime is 21013217. The reversal of 21013191 is 19131012.

It is not a de Polignac number, because 21013191 - 2¹ = 21013189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21013991) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50550 + ... + 50963.

It is an arithmetic number, because the mean of its divisors is an integer number (2639364).

Almost surely, 2^21013191 is an apocalyptic number.

21013191 is a deficient number, since it is larger than the sum of its proper divisors (10659177).

21013191 is a wasteful number, since it uses less digits than its factorization.

21013191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101542 (or 101539 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 18.

The square root of 21013191 is about 4584.0147251072. The cubic root of 21013191 is about 275.9501721643.

The spelling of 21013191 in words is "twenty-one million, thirteen thousand, one hundred ninety-one".