21212240445 has 64 divisors (see below), whose sum is σ = 41269582080. Its totient is φ = 10252051200.

The previous prime is 21212240437. The next prime is 21212240449. The reversal of 21212240445 is 54404221212.

It is a happy number.

21212240445 is a `hidden beast` number, since 2 + 1 + 212 + 2 + 4 + 0 + 445 = 666.

It is not a de Polignac number, because 21212240445 - 2³ = 21212240437 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212240449) 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 63 ways as a sum of consecutive naturals, for example, 448215 + ... + 493275.

It is an arithmetic number, because the mean of its divisors is an integer number (644837220).

Almost surely, 2^21212240445 is an apocalyptic number.

It is an amenable number.

21212240445 is a deficient number, since it is larger than the sum of its proper divisors (20057341635).

21212240445 is a wasteful number, since it uses less digits than its factorization.

21212240445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45403 (or 45397 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 27.

Adding to 21212240445 its reverse (54404221212), we get a palindrome (75616461657).

The spelling of 21212240445 in words is "twenty-one billion, two hundred twelve million, two hundred forty thousand, four hundred forty-five".