21229571 has 12 divisors (see below), whose sum is σ = 23837856. Its totient is φ = 18883920.

The previous prime is 21229501. The next prime is 21229577. The reversal of 21229571 is 17592212.

It is not a de Polignac number, because 21229571 - 2¹⁴ = 21213187 is a prime.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21229577) 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, 3821 + ... + 7553.

It is an arithmetic number, because the mean of its divisors is an integer number (1986488).

Almost surely, 2^21229571 is an apocalyptic number.

21229571 is a deficient number, since it is larger than the sum of its proper divisors (2608285).

21229571 is a wasteful number, since it uses less digits than its factorization.

21229571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3802 (or 3791 counting only the distinct ones).

The product of its digits is 2520, while the sum is 29.

The square root of 21229571 is about 4607.5558596722. Note that the first 3 decimals coincide. The cubic root of 21229571 is about 276.8941238466.

The spelling of 21229571 in words is "twenty-one million, two hundred twenty-nine thousand, five hundred seventy-one".