21270204 has 18 divisors (see below), whose sum is σ = 53766440. Its totient is φ = 7090056.

The previous prime is 21270191. The next prime is 21270217. The reversal of 21270204 is 40207212.

Added to its reverse (40207212) it gives a triangular number (61477416 = T₁₁₀₈₈).

It is an interprime number because it is at equal distance from previous prime (21270191) and next prime (21270217).

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 295384 + ... + 295455.

Almost surely, 2^21270204 is an apocalyptic number.

It is an amenable number.

21270204 is an abundant number, since it is smaller than the sum of its proper divisors (32496236).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21270204 is a wasteful number, since it uses less digits than its factorization.

21270204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 590849 (or 590844 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21270204 is about 4611.9631394884. The cubic root of 21270204 is about 277.0706679772.

Adding to 21270204 its reverse (40207212), we get a palindrome (61477416).

The spelling of 21270204 in words is "twenty-one million, two hundred seventy thousand, two hundred four".