21299229 has 24 divisors (see below), whose sum is σ = 35335872. Its totient is φ = 12110400.

The previous prime is 21299221. The next prime is 21299231. The reversal of 21299229 is 92299212.

It is not a de Polignac number, because 21299229 - 2³ = 21299221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21299193 and 21299202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21299221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13954 + ... + 15404.

It is an arithmetic number, because the mean of its divisors is an integer number (1472328).

Almost surely, 2^21299229 is an apocalyptic number.

It is an amenable number.

21299229 is a deficient number, since it is larger than the sum of its proper divisors (14036643).

21299229 is a wasteful number, since it uses less digits than its factorization.

21299229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1697 (or 1694 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 21299229 is about 4615.1087744494. The cubic root of 21299229 is about 277.1966395150.

It can be divided in two parts, 21299 and 229, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 21299229 in words is "twenty-one million, two hundred ninety-nine thousand, two hundred twenty-nine".