21078229 has 8 divisors (see below), whose sum is σ = 21483072. Its totient is φ = 20677440.

The previous prime is 21078209. The next prime is 21078257. The reversal of 21078229 is 92287012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21078229 - 2¹⁵ = 21045461 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21078229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21078209) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10734 + ... + 12544.

It is an arithmetic number, because the mean of its divisors is an integer number (2685384).

Almost surely, 2^21078229 is an apocalyptic number.

It is an amenable number.

21078229 is a deficient number, since it is larger than the sum of its proper divisors (404843).

21078229 is a wasteful number, since it uses less digits than its factorization.

21078229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2027.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 21078229 is about 4591.1032443194. The cubic root of 21078229 is about 276.2345770551.

The spelling of 21078229 in words is "twenty-one million, seventy-eight thousand, two hundred twenty-nine".