21213011228 has 12 divisors (see below), whose sum is σ = 38736803280. Its totient is φ = 10145353152.

The previous prime is 21213011221. The next prime is 21213011231. The reversal of 21213011228 is 82211031212.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213011221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115288013 + ... + 115288196.

It is an arithmetic number, because the mean of its divisors is an integer number (3228066940).

Almost surely, 2^21213011228 is an apocalyptic number.

It is an amenable number.

21213011228 is a deficient number, since it is larger than the sum of its proper divisors (17523792052).

21213011228 is a wasteful number, since it uses less digits than its factorization.

21213011228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230576236 (or 230576234 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The spelling of 21213011228 in words is "twenty-one billion, two hundred thirteen million, eleven thousand, two hundred twenty-eight".