21244251213 has 16 divisors (see below), whose sum is σ = 31524331840. Its totient is φ = 14139718992.

The previous prime is 21244251209. The next prime is 21244251227. The reversal of 21244251213 is 31215244212.

21244251213 is a `hidden beast` number, since 2 + 1 + 2 + 442 + 5 + 1 + 213 = 666.

It is not a de Polignac number, because 21244251213 - 2² = 21244251209 is a prime.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244251233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 625231 + ... + 658332.

It is an arithmetic number, because the mean of its divisors is an integer number (1970270740).

Almost surely, 2^21244251213 is an apocalyptic number.

It is an amenable number.

21244251213 is a deficient number, since it is larger than the sum of its proper divisors (10280080627).

21244251213 is a wasteful number, since it uses less digits than its factorization.

21244251213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1284185 (or 1284179 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

Adding to 21244251213 its reverse (31215244212), we get a palindrome (52459495425).

The spelling of 21244251213 in words is "twenty-one billion, two hundred forty-four million, two hundred fifty-one thousand, two hundred thirteen".