21102291 has 36 divisors (see below), whose sum is σ = 35864400. Its totient is φ = 11920608.

The previous prime is 21102281. The next prime is 21102307. The reversal of 21102291 is 19220112.

It is not a de Polignac number, because 21102291 - 2⁹ = 21101779 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21102251) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 47850 + ... + 48288.

Almost surely, 2^21102291 is an apocalyptic number.

21102291 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21102291 is a deficient number, since it is larger than the sum of its proper divisors (14762109).

21102291 is a wasteful number, since it uses less digits than its factorization.

21102291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 568 (or 558 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21102291 is about 4593.7229999207. The cubic root of 21102291 is about 276.3396495887.

The spelling of 21102291 in words is "twenty-one million, one hundred two thousand, two hundred ninety-one".