21355371 has 6 divisors (see below), whose sum is σ = 30846660. Its totient is φ = 14236908.

The previous prime is 21355351. The next prime is 21355387. The reversal of 21355371 is 17355312.

It is not a de Polignac number, because 21355371 - 2⁹ = 21354859 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21355351) 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, 1186401 + ... + 1186418.

It is an arithmetic number, because the mean of its divisors is an integer number (5141110).

Almost surely, 2^21355371 is an apocalyptic number.

21355371 is a deficient number, since it is larger than the sum of its proper divisors (9491289).

21355371 is a wasteful number, since it uses less digits than its factorization.

21355371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2372825 (or 2372822 counting only the distinct ones).

The product of its digits is 3150, while the sum is 27.

The square root of 21355371 is about 4621.1871851289. The cubic root of 21355371 is about 277.4399772787.

The spelling of 21355371 in words is "twenty-one million, three hundred fifty-five thousand, three hundred seventy-one".