21572029 has 4 divisors (see below), whose sum is σ = 21666460. Its totient is φ = 21477600.

The previous prime is 21572003. The next prime is 21572041. The reversal of 21572029 is 92027512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 19316025 + 2256004 = 4395^2 + 1502^2 .

It is a cyclic number.

It is not a de Polignac number, because 21572029 - 2¹¹ = 21569981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21571988 and 21572006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21572059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46872 + ... + 47329.

It is an arithmetic number, because the mean of its divisors is an integer number (5416615).

Almost surely, 2^21572029 is an apocalyptic number.

It is an amenable number.

21572029 is a deficient number, since it is larger than the sum of its proper divisors (94431).

21572029 is an equidigital number, since it uses as much as digits as its factorization.

21572029 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94430.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 21572029 is about 4644.5698401467. The cubic root of 21572029 is about 278.3750652364.

It can be divided in two parts, 2157 and 2029, that added together give a triangular number (4186 = T₉₁).

The spelling of 21572029 in words is "twenty-one million, five hundred seventy-two thousand, twenty-nine".