21153311212 has 12 divisors (see below), whose sum is σ = 40383594216. Its totient is φ = 9615141440.

The previous prime is 21153311189. The next prime is 21153311227. The reversal of 21153311212 is 21211335112.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 240378493 + ... + 240378580.

It is an arithmetic number, because the mean of its divisors is an integer number (3365299518).

Almost surely, 2^21153311212 is an apocalyptic number.

21153311212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21153311212 is a deficient number, since it is larger than the sum of its proper divisors (19230283004).

21153311212 is a wasteful number, since it uses less digits than its factorization.

21153311212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480757088 (or 480757086 counting only the distinct ones).

The product of its digits is 360, while the sum is 22.

Adding to 21153311212 its reverse (21211335112), we get a palindrome (42364646324).

The spelling of 21153311212 in words is "twenty-one billion, one hundred fifty-three million, three hundred eleven thousand, two hundred twelve".