21038771 has 4 divisors (see below), whose sum is σ = 22657152. Its totient is φ = 19420392.

The previous prime is 21038729. The next prime is 21038777. The reversal of 21038771 is 17783012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21038771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21038777) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 809171 + ... + 809196.

It is an arithmetic number, because the mean of its divisors is an integer number (5664288).

Almost surely, 2^21038771 is an apocalyptic number.

21038771 is a deficient number, since it is larger than the sum of its proper divisors (1618381).

21038771 is a wasteful number, since it uses less digits than its factorization.

21038771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1618380.

The product of its (nonzero) digits is 2352, while the sum is 29.

The square root of 21038771 is about 4586.8040071492. The cubic root of 21038771 is about 276.0621009529.

The spelling of 21038771 in words is "twenty-one million, thirty-eight thousand, seven hundred seventy-one".