21219745212 has 72 divisors (see below), whose sum is σ = 53893580832. Its totient is φ = 7039728000.

The previous prime is 21219745207. The next prime is 21219745279. The reversal of 21219745212 is 21254791212.

It is a happy number.

21219745212 is a `hidden beast` number, since 2 + 1 + 2 + 197 + 452 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11161462 + ... + 11163362.

It is an arithmetic number, because the mean of its divisors is an integer number (748521956).

Almost surely, 2^21219745212 is an apocalyptic number.

It is an amenable number.

21219745212 is an abundant number, since it is smaller than the sum of its proper divisors (32673835620).

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

21219745212 is a wasteful number, since it uses less digits than its factorization.

21219745212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3219 (or 3214 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The spelling of 21219745212 in words is "twenty-one billion, two hundred nineteen million, seven hundred forty-five thousand, two hundred twelve".