21029771 has 12 divisors (see below), whose sum is σ = 24622632. Its totient is φ = 17908128.

The previous prime is 21029747. The next prime is 21029779. The reversal of 21029771 is 17792012.

It is not a de Polignac number, because 21029771 - 2¹⁰ = 21028747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21029779) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6671 + ... + 9303.

It is an arithmetic number, because the mean of its divisors is an integer number (2051886).

Almost surely, 2^21029771 is an apocalyptic number.

21029771 is a deficient number, since it is larger than the sum of its proper divisors (3592861).

21029771 is a wasteful number, since it uses less digits than its factorization.

21029771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2810 (or 2803 counting only the distinct ones).

The product of its (nonzero) digits is 1764, while the sum is 29.

The square root of 21029771 is about 4585.8228269308. The cubic root of 21029771 is about 276.0227305721.

The spelling of 21029771 in words is "twenty-one million, twenty-nine thousand, seven hundred seventy-one".