21213945552 has 20 divisors (see below), whose sum is σ = 54802692800. Its totient is φ = 7071315168.

The previous prime is 21213945547. The next prime is 21213945559. The reversal of 21213945552 is 25554931212.

It is a self number, because there is not a number n which added to its sum of digits gives 21213945552.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213945559) 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, 220978552 + ... + 220978647.

It is an arithmetic number, because the mean of its divisors is an integer number (2740134640).

Almost surely, 2^21213945552 is an apocalyptic number.

It is an amenable number.

21213945552 is an abundant number, since it is smaller than the sum of its proper divisors (33588747248).

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

21213945552 is a wasteful number, since it uses less digits than its factorization.

21213945552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441957210 (or 441957204 counting only the distinct ones).

The product of its digits is 108000, while the sum is 39.

The spelling of 21213945552 in words is "twenty-one billion, two hundred thirteen million, nine hundred forty-five thousand, five hundred fifty-two".