21472229 has 4 divisors (see below), whose sum is σ = 21713580. Its totient is φ = 21230880.

The previous prime is 21472219. The next prime is 21472249. The reversal of 21472229 is 92227412.

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 2244004 + 19228225 = 1498^2 + 4385^2 .

It is a cyclic number.

It is not a de Polignac number, because 21472229 - 2²⁰ = 20423653 is a prime.

It is a super-2 number, since 2×21472229² = 922113236456882, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21472219) 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, 120542 + ... + 120719.

It is an arithmetic number, because the mean of its divisors is an integer number (5428395).

Almost surely, 2^21472229 is an apocalyptic number.

It is an amenable number.

21472229 is a deficient number, since it is larger than the sum of its proper divisors (241351).

21472229 is an equidigital number, since it uses as much as digits as its factorization.

21472229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241350.

The product of its digits is 4032, while the sum is 29.

The square root of 21472229 is about 4633.8136561584. The cubic root of 21472229 is about 277.9451136403.

The spelling of 21472229 in words is "twenty-one million, four hundred seventy-two thousand, two hundred twenty-nine".